MacForge VS ThemeEngine

The only thing I know of is moreMenu but it requires MacForge which unfortunately means it probably requires disabling SIP. It also may not be M1/M2 compatible.

long answer: - install MacForge. it's a plug-in loader for macOS

You can change even to any image if you hardly want to, but at a cost that I would not bother with. There is a plugin for MacForge that changes UI parts https://github.com/MacEnhance/MacForge

I remember being a big fan of the app "flavours" (theme park was before my time), and was really excited to see "flavours 2" come out, until the new osx version completely changed how themes worked and the devs just gave up, since all their work was now outdated. I then got into theme engine, which seemed really promising. It seems like nobody ever really put the effort in tho to figure out exactly what assets led to which visual elements in the OS. I straight up brute forced my way into having a dark themed finder to match my terminal windows before mojave came along with a dark mode. It felt good to finally get it but god damn it was not worth the effort. I once tried to entirely get rid of the traffic light buttons to control windows in the corner. I went through every asset in theme engine and straight up deleted everything that had a traffic light in it because it was super unclear which ones to be editing, and it was faster to just delete than edit them as a transparent png. Broke my whole system, couldn't boot the PC. Went to an apple store and had to talk to 5 or 6 different people before somebody understood what "can i just use a TB to TB cable and a macbook for 30 minutes so I can target disk mode my laptop and replace my broken .car files with my backup?" Still didn't work tho, system restore only option. Turns out 90% of apple store employees only know how to clean out iphone charge ports with a toothpick.

install ThemeEngine. it's an app to modify .car files, which is the file format used for macOS themes

Theming is still possible on macOS/Mac OS X. Just go to r/OSXTweaks or Github and there are many people theming macOS Big Sur because they don’t like the look. Besides, people will love support for theming and it isn’t too hard to add in. Last but not least, Apple is getting nostalgic these days, so it seems fit for them to add theming features as theming was easier in the old days.

Here is a fix for that: https://github.com/alexzielenski/ThemeEngine/issues/63 (Have not tried it myself)