I remember one time I installed a lot of themes for my session and I broke something and the themes changed my icon files forever and I had to reinstall Ubuntu!!
Should I just stick to changing my wallpaper and other small tweaks? I don’t really like using vanilla Ubuntu anymore, it doesn’t feel like me. Thank you very much!!
Use something other than gnome and, while you’re at it, you might as well use something other than ubuntu.
KDE is very hard to break, you can go wild with customization there.