Just install terminfo.

It is intended behavior, almost every terminal requires terminfo. It is just that terminfo for most popular (or older) ones comes preinstalled.

All new niche terminal suffer from it. Foot has the same problem.

The main problems with gaming on x11 are:

1. Screen tearing. You can check YouTube for how it looks.

2. Latency in x11 is significantly higher.

3. HDR support. X11 does not support HDR. But I doubt you laptop supports it either.

I do not believe that problems 1 and 2 affect minecraft that much. They are mostly prominent in games like first-person-shooter and alike.

Also, note that Minecraft itself does not support wayland. This means that it would run under x11 that would run under wayland (with both x11 and Wayland problems combined).

I am not sure that using Wayland is your best choice here. Based on laptop specs it is not like you are going to game on it. And for web and office tasks x11 still offers a better experience. On Wayland you would have problems with things like scaling, screen capturing etc. They are (to some extend) solvable, but are tricky to fix, especially with your lack of terminal experience.

Also I would not care that much for cutting-edge repositories. They are usually required for support of the new hardware (which of cause is not the case here).

Also, almost all modern DE are somewhat the same in terms of resource consumption. Some are a bit heavy (for example Cinnamon is heavier than xfce) but the difference if almost negligible. The majority of resources would be consumed by a browser, not DE. If you still wish to have the lightest DE possible, than you are limited to LXQT. XFCE nowadays is not as light as it used to be. You can have a very good performance with window managers like openbox and alike. For panel you can use polybar, tint or whatever. But that would require some configuration from you. Such setup is available in MX Linux. I suggest you to take a look at that distro, it is kinda good for old laptops. Of cause, standalone Wayland compositors (sway, hyprland, labwc, wayfire etc.) are very good, but they would require you to do a lot configuration work to set everything working. Even distros that ship them preinstalled (like Fedora Sway spin, for example) have somewhat broken defaults.

I doubt it. Today there is a huge trend towards censorship in the world. And ECH is exactly what a censor would not want. It is already blocked in Russia after Cloudflare enabled it by default and I would expect it to be blocked in the west “for anti-piracy reasons” very soon.