So maybe SDD will improve sync, I will try that.
That's not a "maybe", it's a given

I keep my "blocks" directory on my old hdd, and the rest of Bitcoin Core on ssd. Especially the chainstate-directory benefits a lot from much faster storage.
I'm seriously considering getting my coins out of the wallet when I'm synced
That would be a waste: once synced, you'll never have to go through this again. Just keep Bitcoin Core running and it downloads 6 blocks per hour to remain fully synced.