Yes, he's old and barely pitched. But he was decent when he did pitch.
If you assume Pivetta and Flaherty will not sign pillow contracts, and Clayton Kershaw is a Dodger or not pitching, then here are the sort of viable SP who might sign a one year deal:
Scherzer
Heaney
Hart (KBO guy)
Lynn
Gibson
Quintana
Flexen
Corbin
Stripling
I would guess that Heaney and Kyle Hart want multi-year deals still. I would also guess that half of this list is replacement level in 2025.
So, easy to see the appeal of Scherzer. He might be the only SP on a one year deal who could give a team 2.5+ WAR and start a playoff game.