Linux is actually kinda designed to be less fragmented than windows really.
The reason you don’t pick an install directory is because the standard is that binaries live where binaries live, dependencies live where dependencies live, logs live where logs live, etc.
All the user should worry about is where the media or whatever your program works with is.
Always try to find the apt install instructions for whatever program you want, and it’s easy to uninstall with apt remove.
Apart from a few deb packages, almost everything that can’t be managed via apt should be considered incomplete or experimental. If it was ready for you to just use it without issue, it would be in an apt repository.
It may seem a bit daunting to have to use command line at first, but once you’re used to it, you’ll realise how absolutely broken and archaic managing software on windows is. (Like seriously, it’s 2024 and you’re still having to fish through slow or sketchy websites to find installers for tools and drivers.)
It doesn’t have to be a solemn vow. The definition of insurance is that it’s a guarantee. If it’s denying claims it’s technically not even providing insurance.