Question About First Publishing Rights

Hello! Apologies if this isn’t the right subreddit for this question, but I have some concerns about first publishing rights.

For context, I am an aspiring writer currently working on my first WIP (I have not published anything). I am also a digital artist and enjoy making illustrations of my story’s characters and world in my free time. I have been thinking about posting my art online (like on Tumblr or Instagram), but I am concerned if doing so will count as publishing and thus hurt my chances of getting traditionally published.

I understand that traditional publishing itself is rather difficult, and my chances are small as is, but I don’t want to completely burn that bridge before I even begin querying (just to keep my options open). Any thoughts on this, if it’ll ruin my chances or not?

Is there anything I should avoid if I do decide to post my art? For instance, on social media I often see people give descriptions of their own characters (including backstory and personality) when posting art of them. Should I avoid doing that?

Thank you for your time!