I’m pretty sure you’re going to have to use a live USB. You can’t modify a partition while it’s mounted and you can’t unmount a partition that’s in use.

Just go with Mint. However, if you want to get the most out of the device, you’ll need to use linux-surface and that will involve a little command line usage to setup. Fortunately, the project has detailed instructions..

You would just install one of the KDE meta-packages. After that you can select the new desktop environment when you login again.

The only thing to note is that some settings don’t always play nice between the two (for example one might overwrite settings on the other), so maybe consider making a new user account just to see if you like it.

What desktop environment are you using? KDE let’s users do this pretty easily by just going into the color scheme settings. I’m not sure what the process is for other desktops these days.

Is it 32-bit? If it is, then that also severely limits your options. Personally, I just throw Debian or one of its derivatives on old hardware like that. You may want to consider Q4OS. It’s Debian based and is geared specifically towards old and low-end hardware. Interestingly, it’s also one of only a couple distros that ship with Trinity as a desktop environment.

Retro gaming is definitely doable with 2GB of RAM, considering that older Raspberry Pi boards can do it with just 1GB. In that case you could try Batocera.

Some other ideas include running something like Nextcloud or a media server on it on your home network. In that case, I’d again recommend Debian.

The panel is handled by the plasma theme. I’m not sure what’s the cause of your issues. Normally transparent themes work out of the box on KDE. I’d do some testing on one of my spare computers to try and figure it out, but I’m busy the next couple days.

It’s possible the global theme you installed didn’t pull the plasma theme with it. Did you try installing just a plasma theme? Additionally, did you install the theme manually (by placing the files in the correct directory under /.local/share) or automatically (through Get New Themes or Discover)?

I think you can do that with AntiMicroX.

I wasn’t aware that there’s a paid version. Based on their website it does look like they have a lot of standard stuff locked behind Pro. Is it just like an additional repo or something? I’m also not too keen on the fact that the upgrade doesn’t carry over to the next major version.

I’m pretty sure that’s Zorin. I’ve never used it myself, but from what I’ve heard it might be a good choice for OP’s person.