here's a quick and easy way I add threads to my 3D prints in Blender! There's a few ways to go about it but this is the easiest way I have found. You will probably want some calipers for this one if you're matching preexisting threads so I've linked some inexpensive ones from amazon I'd buy if I needed some new ones.
https://www.amazon.com/WEN-10761-Electronic-6-1-Inch-Digital/dp/B07HFTFCFV/ref=sr_1_14?crid=6YJ8Q5RIQW9H&dib=eyJ2IjoiMSJ9.4pZ6x2l-IIAAWYVRBatMEmoTz6XShSnZl2UMIe0JUNN7wlZNFu00EGGN4SJYeOpqgtgzAhqB-z7JtLMPt68AgJZ7ViTwOTObeIA243vGwdm8G3g3Lm7EYsS68SAyujAfiJycoC0XINaacZeymNatuMbBkLdE_DXDvPe49zMtIrgxLDyi6hXXOoCuK11jR5l5tZqVZ-V0H3V3znYUOT8vEqoDzIP19IX9ryqKVGFmWb8.THPDv7p5eOt9t5cizpb8dQYyZO896UgvvzhfKuxaNoA&dib_tag=se&keywords=calipers&qid=1731040816&sprefix=calipers%2Caps%2C184&sr=8-14&th=1