You say that like an i7 with 16GB RAM, and a GeForce GPU can't game. The hardware is more than good enough (within reason - these are 15+ year old games). It works fine in Windows 10. Normally Linux support for older drivers is better than Windows; Nvidia is the exception.
I fired up a little test with Terraria and it worked, though that one likely would have worked under nouveau. I'll do a more solid test during the week.
When I'm at home, I have a beefy desktop that I can play modern games on. I'm going away for two weeks at Christmas and want to have some simple games to relax with. I'm debating whether to take my MX 3S mouse, or something more portable. I'm not likely going to be able to justify an eGPU.
Besides, the laptop only has Thunderbolt 1 with theoretical max throughput of 10gbps. I doubt I'd get much better than a RX560 going on it - which while supported isn't really worth the effort. Now that I think about it, I could pick up a second-hand Thinkpad x280 for around the same price and be in a far better spot. That was actually my starting point, I was going to grab one of them before I decided to stretch the life out of this laptop.