I'm in the exact same boat as you, exact same specs. CPU/GPU holding up perfectly for my use cases, but 512GB is tough to manage now.
I checked used prices though, and I think the market is not in our favor. rebuy.de has an M2 Max with 32 GB/1 TB configuration in "very good" condition and is asking 2100 Euro for it.
M6 is "just" 600 Euro more...