Much like Windows 8, most people on Windows 11 tend to be the technically-disinclined, which generally are not the userbase of an experimental alternative browser. Thus I too, am understandably baffled at the lack of Windows 10 support.
Technically you can force your way to install Arc on Windows 10[1], but it was a rough experience when I tried few months ago during beta.
[1]: Guide to installing Arc Browser on Windows 10 - https://gist.github.com/TrevTV/2044e43666a8fa4bb581d4b0c8316...
Unlike Vista and 8, nothing broke and everything is where I expect, so I've stuck with it.
Who is running 2GB of ram these days? Win 11 recommends 4GB, and imo that's very little on a modern computer. 8GB for casual use, 16 for anything more intensive.