Need help with work and a verbal warning

Full disclosure, I started working at a food manufacturing company 9 months ago in the “maintenance” department. I (39F) had initially loved the atmosphere with the other people in my department and on my shift (mostly men). I had thought there was a friendly vibe going on and “free talk” was kind of just what people did. What I mean by that is - use language that would be considered unprofessional in most office spaces.
They guys would make all kinds of “shop” comments and jokes about everyone there, it was an atmosphere I was happy to be apart of. Shop comments being about sexuality,racist stuff,and the kind of things men say to each other.
I’ve grown up my whole life being around this kind of environment. Have worked in factories as a college summer student, and worked in male dominated fields my whole life. So it felt “like home” when the guys were, at least I thought, friendly about it and joking.
Over the last few months I’ve started to notice the “change” a lot of people would talk about. When I first started, I was a little blinded by the new job excitement. But the 2 other guys who started with me have both already left, stating “it’s not the same”. They were previous employees who returned and quickly left.
In 9 months, a total of 7 people in our department alone have left (one even rage quitting without notice). It started to become a different environment and something I couldn’t ignore anymore. There was 2 other people hired a few months after me who share my position, and were not as efficient in their work as previous staff I started with. It was frustrating.
Over time I was assigned all of my positions work orders weekly, sometimes getting 5-6 assignments (on top of my regular duties) that would amount to 15+ hours of work, while the others in my position were getting none. I mistakenly asked for these to be shared and divided out better once the newer then me guys were trained, and this led to me not being assigned any work orders for my role and instead started getting production belt replacements, something I was shown once but not qualified for (or paid for).
There were tensions that blew up recently over a 2 week production shutdown period. I was assigned the entire production line belt changes over the course of this period while the actual qualified maintenance guys (I’m maintenance department but not actually maintenance) did a few things but spent most of their weekend shifts playing cards while I ran around and barely had enough time for my regular duties on top of the assignments, even taking 10 minute lunches and skipping breaks all together.
My role and the maintenance guys have different hourly wages. So after a few frustrating weeks, I went to a fellow coworker (who had been off during those two weeks and only a few days away from retirement) and showed him an email I was considering sending. This email was more of a frustrated email and I was likely not going to send it after waiting my normal 24hr rule. But I wanted to talk about it with someone. I was basically asking if I would be compensated for my time spent doing the work of someone in the maintenance department?
Well this guy had beef with that. A discussion started and he mentioned something about “I don’t say anything when you’re doing F*** all”. Something I obviously took offence to as I am generally working most of my shift before I go to break, and they are often sitting around waiting to go for break when no management is on site.
I asked him when I was ever doing “that”, to which he couldn’t answer, and then I mentioned how I see him and the other guys just sitting around waiting for break most of the shift- something he considered as me calling them all lazy and obviously took offence. The convo turned more sour but voices stayed level (in my view), it amounted to him basically saying “okay F you, why don’t you just F off”
I immediately turned around and went to leave and unfortunately said “okay, f you too” and walked out.
This happened in a large open shop area, no one else was even in the room, but apparently a witness came back and this coworker complained about me using foul language and yelling. I was brought into an office on my last shift (which is also his last shift, he retired) and given the verbal warning for it.
I really don’t know who to do, cause a moment of frustration ended in a verbal warning and a partial investigation. My union has already said they deny the first step of grievance everytime. So it’s going to be a fight. The shop where it happens has swipe in access and cameras on both exit doors, so I’m inclined to ask them to check for an actual witness being present in the room.
But here’s where I need advice. The shop behaviour is reportable. Not just the language and comments, but things done in after hours and weekends. I’ve not even been there a full year and I’ve known about times my coworkers have DRANK on the job. I would smell it coming into rooms, but just figured it was some kind of cleaner (hoped), assuming the best because I’ve honestly never been in an environment where ppl just drank at work, openly. It wasn’t just one person, it was every person on my shift (excluding me, cause wtf). They had even offered me some a few times, so questions eventually answered themselves and it was confirmed. I didn’t say anything because it was literally everyone but me doing it, and I didn’t actually have “proof”. I just avoided them when it would happen. Trying to be liked, if I’m being honest.
But now that this verbal warning has come in over this incident (which I’m not fully innocent, but giving a warning to someone who is doing the same behaviour as the complaining coworker without any investigation other then talking to a witness who wasn’t there, and coworker retired making it impossible now to give a warning to them is just bs) I’m kind of feeling like taking notes of the comments, for an eventual complaint on my part but know this will get seen as retaliation if not done right. I’m also not feeling like turning a blind eye to the drinking anymore, but again - retaliation. And tbh I probably am doing it out of spite… but I let a lot of comments and actions slide just thinking it was friendly banter only to find out I’m clearly not their friend and they tossed me under the bus hard.
So any help on any of it would be great.
Am I just being a big baby and retaliating if I report them drinking next time? (It’s a maintenance shop)
I’m 39, and honestly have never been in this situation before. I’m pretty sure my work is trying to get rid of me, so as I’m applying to other jobs… what do I do if I suspect or even catch them drinking again, or making inappropriate comments?