Your best bet would probably be to get a used office PC to put the card in. You'll likely have to replace the power supply and maybe swap the storage but with how much proper external enclosures go for the price might not be too different. Some frameworks don't support direct GPU loading so make sure that you have more ram than vram.
An arm soc won't work in most cases due to a lack of bandwidth and software support. The only board I know of that can do it is the rpi5 and that's still mostly a poc.
In general I wouldn't recomend a titan x unless you already have one because it's been deprecated in cuda, so getting modern libraries to work will be a pain.