If you trade for Hosmer, you essentially have him through 2025. Why would you want him.
Since signing with SD:
2018 95 WRC+
2019 91 WRC+
2020 127 WRC+
2021 99 WRC+
Is he really having a "down year" or is that just who he is? He's not great defensively. He's average (at best) offensively. That's not a guy you get locked into long term.