Ex Employer Sent Demand Letter And Threatening Grand Theft+ Professional Board Complaints

I was let go on January 2025 by my ex employer. He cited several reasons like I wasn't doing my job properly, fired me on the spot, no notice period. When I got to the office, my desk had already been cleared. I did not fight back and found a different job which I already started. Did not claim unemployment either. Just want to move on with a fresh start.

However, in beginning of February he sent me a demand letter saying id copied company files into my personal computer and he wants to inspect them and/or charge me for grand theft and/or delete them. If I did copy anything, it would be to try and work remotely and for company purposes. He helped me setup the remote access. Honestly I'm not sure what files he means, but I haven't used anything outside company work or after he fired me. He also said id acted against my professional code of practice and would report me to my board. I want to move on, and I will take my computer for his inspection sometime this week and he can inspect and delete what he wants.

But i really can't trust this guy and I feel like he's gonna try this again in the future so I was thinking of taking some letters of acknowledgement for him to sign. Is that a good idea or will it make matters worse?

Just some affidavits that states facts like I did indeed bring my personal computer for inspection. And that he has no knowledge if I even used any of these for my personal gain. Or that in December I took a week off with his verbal approval but he later said he was not going to pay, which I countered saying I'm entitled to 10 days off per our agreement, which he later admitted to be true. And that he called me to work during company vacation period (Christmas weeks, and the vacation is in the employment agreement), to which I said sure, but if I was compensated for the time separately (that's when he started losing it). Or that he withheld some reimbursements for projects id done, that he said he would not pay. Or are these things I should keep to myself and bring to a lawyer if things goes south?

Sorry long post but any insight id really appreciate thank you.