This

To add to this, OP may want to put their thoughts down in writing. An email or memo or note or anything as long as it’s not a text or other personal non work form of communication.

Lay it all out, over write it, put too much detail and then pare it down to what OP believes to be acceptable. Have some copies of it.

Give them the written missive that boils down to “leave me alone” Make a note of the time and date.

If the co-worker keeps being a pest, go to HR, with a copy of the missive, and a note of the date it was given to co-worker so that co-worker cannot wheedle their way into making it about them trying to “help” OP.

Also, fuck every co-worker who pulls unprofessional shit like this. It’s abhorrent and borderline harassment.