If you actually tried and really can't see how living by the gospel of Stallman would impose severe restrictions on how you use your computer then I'm afraid I can't help you.
Still, a few examples to illustrate
I wouldn't be able to use Word attachments (https://www.gnu.org/philosophy/no-word-attachments.html)
I wouldn't be able to use Windows (https://www.gnu.org/philosophy/upgrade-windows.html)
I wouldn't be able to package useful non-free software for my Linux distro (https://www.gnu.org/philosophy/compromise.html)
I would have to call the Linux distro a "GNU/Linux distro" (https://www.gnu.org/gnu/why-gnu-linux.html)
I would have to ideally stop, but at least reduce, my usage of WhatsApp, Facebook, Slack, etc. (https://www.gnu.org/philosophy/saying-no-even-once.html)
These are just all-in-all minor examples I could find in a couple of minutes on gnu.org. I remember reading much more radical takes by Stallman and his companions, but would have to spend more time searching for them.