There is a Full HD screen on my 14" laptop. It looks like some sort of HiDPI for me, and that is why controls of an interface on native resolution are too small, so it’s difficult to use. On Windows, an interface was scaled for 125% and looks a lot better.
I tried to make the same settings on Ubuntu 21.04, and there were some issues. There are two options: a new Wayland session and a more traditional Xorg session.
When I set up a 125% scale for the interface in the Wayland session, it looks great, but some apps like Google Chrome, VS Code, or Slack look blurry out of the box. For some apps, it’s possible to fix it in some way using experimental features, that can lead to instability and random crashes. Also, there is an extremely annoying bug in Firefox: some popups like Multi-Account Containers are cropped and it’s impossible to use them. It will be fixed only in Firefox 93 which will be released in October. There are a lot of small issues on Wayland like Vim clipboard, that is why I’m not sure that Wayland is ready for desktop now.
When I set up a 125% scale for the interface in the Xorg session all apps work properly, but there are some artifacts in the interface like black rectangles around windows or black lines in random places of the screen. It’s better than Wayland but still not good enough.
I’d tried different Linux distributions and different desktop environments to find the best solution for cases like mine. Xfce and Cinnamon work fine only with x2 and x3 scales. Elementary works with x2 scale and allows to increase fonts, so texts look fine, but controls are too small. The co-founder of Elementary says it’s OK and I just need to buy another laptop.
The solution I found is Kubuntu 21.04 with KDE 5.21.4. It allows setting 125% scale out of the box. Everything works: Qt apps, GTK apps, Firefox, Google Chrome, and so on. That is why now I’m a happy KDE user.