O'Hoppe has value, but there were still a lot of questions whether he projected as a starter at the ML level. On a pure value play, O'Hoppe > Marsh, but in terms of team needs and the depth chart, Marsh has more short-term value.
And he'd been in Lehigh next year, Stubbs as a LH bat makes more sense as the backup catcher on a playoff team.
Marsh has more value to this team this year and next season, after that, O'Hoppe had more upside, but probably wasn't going to start until 2026 (if they don't extend JT). By that time, Perez might be ready.
I think the play of Stubbs and Sands made O'Hoppe expendable, they've both exceeded expectations, and the Phillies have always like Marchan.