Is TB1 viable?
There are a few cheaper and/or interesting boxes from time to time on eBay which only have TB1. My laptop has an Alpine Ridge LP so it's already limited to 20 gbit -- i know TB1 is 10 gbit I am just saying I am not losing that much 🙂 And PCIe 2.0 x1 adapters are fine so bandwidth wise I am not worried. I am wondering whether the Apple adapter would work and whether there are any other challenges I am missing.
You can find some test here, comparison table and also some YouTube video showing good performance. TB1 will limit you but also older computer with tTB1 will be a limit. Use a mind range GPU and you will have a nice boost compared to integrated. Try to find a cheap RX 470/570
eGPU.it | LG 34" 4K 34UC88 curved ultrawide display
MacBook Pro 2018 Touch Bar i7 quad-core 2.7Ghz - 16GB RAM - 512GB PCIe SSD --> my Mantiz Venus extreme mod with Sapphire Nitro+ RX Vega 64