The 16xx (Turing) are the same chips as the 20xx big without Ray Tracing capability. The Quadro T600 may be found cheaper than the 1660Ti since the latter is still is very popular gaming card. I’m still not 100% sure what you really need a GSP for in your setup and I really don’t know why you’d need any gpu to run Home Assistant unless you are running a local LLM as a speech assistant
I’m not sure about AMD but for Nvidia it can matter which generation of NVENC and NVDEC chips you have, as well as the number of them. Myself, I use the P400 which is pretty much a 1050.
If you don’t need to update the drivers per se for it to work I would suggest freezing updates. Drivers won’t change anything about the raw GPU power anyway. They usually just fix game compatibility.
https://developer.nvidia.com/video-encode-decode-support-matrix
Gas heating is much more effing than electric heating so it all depends on your situation whether you can heat a room quicker and cheaper with electricity. It is true that every degree you heat above the ambient temperature requires more energy the higher you go, but that’s also true for electricity. If for example it takes you 300kJ to heat your room one degree, gas will get you to that degree with about 380kJ whereas it will take an electric heater well over 500kJ. This might still be profitable for you if you can get enough solar power or if there is a huge discrepancy between electricity and gas in your contract.