Pop or mint like everyone else suggests.
There are only a handful of major distros that are significantly different from each other (debian, fedora, opensuse, arch, nixos) that all other distros base themselves on. Apart from that, for the most part, the difference is basically what desktop environment they install by default, what apps get bundled, and maybe a few more tweaks here and there. It’s easy enough to change all of that regardless of what distro you end up on.
Pop and Mint are based on Ubuntu (which is based on Debian) and will probably have the most resources for support for new linux users. They come with default programs and custom software which makes the new user experience easier.
If you have a problem in either one of them, or want to do anything more complex than install software or tweak settings from a gui, and you can’t find what you are looking for in pop or mint forums, you will likely be able to find the solution in ubuntu forums, or even debian support groups. If you are using a computer that’s relatively new and wasn’t built with linux compatibility in mind, it’s not unlikely you will run into an issue that you’ll need to search out a fix for so it’s good to have those resources.
If the distro you choose doesn’t handle your monitors right, it might be a problem with the desktop environment you are using and it’s typically easy to install an alternative to try out before you nuke the whole thing to try again.
I loved it. Some areas are a bit empty, bosses are balanced wierd sometimes, yes, but it didn’t seem any harder than the hardest parts of the main game, but I also explored as much as possible before tackling bosses so I was pretty powerful at that point, and I use summons at every opportunity just to draw the fire of the hard bosses because I don’t like having to dodge perfectly for five minutes just to get a couple hits in, and then be one shotted by an AoE attack in the second phase.
I had a great time just slowly and carefully exploring most of the DLC. Making it to the cerulean coast was just
. I really enjoyed the haunted woods, too, even though it turns out to be a pretty small area with not much in it as a reward.