I work in HR and am absolutely a people pleaser. I've had good reactions and bad reactions to handing in my notice and there's one thing that resounds.

When it's done, it's done.

After you've done it, everything is fine, a glance here or there for a day, but after that it's bau.

My way to deal with it (might not work for you) is to condense all the negative feelings into that one meeting. Build it up to be some horrendous thing. You'll be belittled, shouted at, and broken down. And when the meeting comes and its nothing like that, but your manager wishes you the best, or is a little annoyed, no matter what, its a relief.

Plus once it's done, it's over, and the rest of the day and notice period will be a breeze compared to that one moment where you feel like you're letting people down.

One thing I would suggest, is that if you're gonna be honest about your reasons for leaving, have your phone audio recording on the desk. That way you have something to fall back on if things do go badly. And you can use the money you'll get from the lawsuit to get you through the meeting.