I have a similar rig, but a 10th gen i7, 128GB of DDR4, 2TB NVMe, and dual RTX 3090s. Built it in 2021 for crypto mining, it ended up paying itself off just before Eth went PoW. I kept it mining even after profitability, because it ran warm enough to heat my apartment leaving my HVAC on fan-only to circulate the heat around.

After winter, I started playing with various other GPU loads until LLMs and SD became easy enough to use. Now it's my experimentation machine.

It's already paid for itself, so anything I sell it for would be profit, but it is still super nice for running local LLMs that power various projects "for free".

You might sell it for more but buying a replacement costs even more so you’re losing money either way. The only way is to sell and never look back.