My main recommendation is stick with one of the major distros because you'll get more results when you search for solutions to issues. With Ubuntu you'll find more hits for specific problems, but I think the quality is also sometimes lower. Whereas I think Arch has the best documentation (for linux in general, not just Arch) but in general you'll need to understand more about what's happening under the hood.
Granted, I probably use less programs than most people, and I'm the type of person who would rather download the nodejs tarball and update my PATH than use the system package or nvm.
The sluggish performance you're getting is honestly probably related to CFS (the default linux process scheduler). Windows does an AMAZING job with scheduling for UI applications. You almost never feel like your computer is struggling because anything UI related gets scheduled first. CFS does not do this.
I've found that changing the scheduler to something that may be less efficient overall, but is aimed at desktop use makes my experience so much better.
Honestly the dark theme of the Gnome variant is the most beautiful dark theme I have ever found for a Linux DE. I know there are lots of ways to tweak the various DEs to get some cool looking dark themes, but my experience is that they can take a lot of manual configuring and tend to still fail on the edge cases. The dark theme bundled with Manjaro Gnome looks amazing right out of the box!