Lowe would at least be flippable before he's a FA. They could keep him for all of 2025 and trade him next offseason. By 2026 Shaw as well as Triantos should be able to play the infield in the MLB, and there will be a bunch of DH options or guys to play OF and put Seiya at DH like Caissie, Alcantara, Ballestos etc. plus other options in trade or FA.
In 2026, unless you can get a clear upgrade like a Soto or Vlad Jr, I like the idea of OF/DH filled by Happ, Seiya, PCA, Alcantara, Caissie. That's 5 guys for 4 spots and 3 of them are dirt cheap and hopefully provide a bunch of surplus. The money saved (e.g. like the 27.5m spent on Bellinger this year) can go towards a Soto/Vlad type or a TORP, a good catcher, or any other high-end player.
My ideal would be to sign Soto (obviously), keep everyone mentioned for 2025, trade Happ next offseason or at the 2026 trade deadline (he'll be a FA after 2026). 2026-2027 would be OF/DH of Soto, PCA, Suzuki, Alcantara/Caissie if all works out. In the mix on INF would be Swanson, Paredes, Shaw, Busch, Nico. Nico is FA after 2026 or is traded before that. Cam Smith ETA as a potential regular is probably 2027.