Honestly it’s no big deal. You have someone who has caught you up, and hopefully you got all the stimulus money at the same time.
From here it should be quite easy, just a few forms each year that once you get comfortable with them, and job done.
Loads of us have US citizenship and have mortgages, pensions, and aren’t fearful, mainly because we know what we know. You’ll be fine, just need a bit of time to wrap your head around it all.
You could always renounce but honestly, I think it’s more faff than just the forms each year.