Over time, as CPUs get better integrated graphics, it might be worth it. Essentially, if you’re fine with playing last-gen games at ok framerates and you don’t need maxed-out graphics, a mini PC is an option. If you want to play recent AAA blockbusters at 100fps, obviously it’s a big no. But the next generation might get you close to those results on current-gen games.
I use Surfshark as well and have your problem 1, as I assume most VPN users do, but not your problem 2. My connection and speeds seem pretty stable, even allowing me to max out my connection many hours later.
Perhaps the issue is which server you’re connecting to.