What Nala1977 said - I would not
I really think buying old technology combined with a high end cpu is not what will keep you happy for a long time.
Not because of Terragen - the development cycle is much too slow to get you in trouble (like Nala1977 mentioned)
- but with the rest of the pipeline.
ZBrush, Speedtree, Marvelous and maybe even LightWave (surely Blender) and not to forget all the software dealing with
Materials and Rendering nowadays are all using the GPU more and more.
The Pandemic and the Bitcoin- (and all the others) hype will be over at some point but, prices won`t go down in the foreseeable future.
But I wrote all this in the other thread(s) already, I guess. Since your thinking (about hardware) seems to be predominantly determined
by "good enough" (this one comes up again and again) I would imagine I am not a good advisor for your decision process, haha.
I always like to add the extra headroom. Once the money is gone, it`s ok anyway. So why not spend it on the best you can get atm?
Saving for a big journey instead? - but WHEN will that be happening again? (just a joke at the times were living in...)
CHeers, Klaus