My (w2) job laid me off and asked me to sign a w9 to get my final paycheck. Is this tax fraud?

I just got laid off last week after being a full time (w2) employee for almost ten years. It's my first time getting laid off, so I have no prior experience in this department. On the same day I was laid off, my employer sent me a w9 to sign so that they could pay my severance, PTO, and wages since my last paycheck. I figured it was standard protocol, so I trusted them and signed the w9 and then got my severance pay a couple of days later.

After that, I came to learn that it might have actually been a red flag for them to have me sign a w9 when I've always been a full time employee. They are basically treating me as a contract worker to get my final paycheck, which would then leave a huge tax burden on me in 2027.

I contacted a tax expert and they said that it's definitely a red flag and that I should declare this situation to the IRS. I have been trying to contact the IRS since Monday, and have been hung up on or on hold for hours only for the call to drop. So I have not had any luck talking to anyone there.

What was already a stressful situation, has become so much worse by having to figure all of this out. I am hoping not to have to involve the company, as I don't trust them to be honest with me or to have anything but their own best interest in mind.

What I've found on the IRS website and on Google searches is that it will be flagged that I have both a w2 and a w9 from the same employer, which will raise flags at the IRS. It also said that most tax websites (Turbotax or Free tax USA) have a button that basically says, "I am submitting a w9 that should have been a w2" which makes me think this is not a rare occurrence.

Does anyone have any advice on what steps I can take to make sure that I am not put in a position where I'm paying my company's taxes or having a much bigger tax burden than I should? I am feeling very dumb and naïve for trusting them. The HR person has always been pretty bad at her job. She is the owner's sister, so that's how she got her job, so not someone I would trust to do her job correctly. So I am hoping that's it's just incompetence, and not sneaky or malicious behavior.

 Any help or advice would be greatly appreciated!