Where to sink my copious items.

I do a similar thing as you. It's good to always make room and allow more things to come your way. Berries can be converted to stardust at a matching gym, so never trash them. I am known to throw Golden Razz at semi-challenging catch pokemon when I get over 80, just to save on balls and time. 5 Star raids put out a ton of Golden Razz.

That said, the only legendary, that you listed, which I would bother with is the 26.5 Ho-Oh. Take that one all the way, and feel free to TM it. TMs take up bag space too, burn em and then hunt for a new one when you need it. I think ES, SB is considered to be the best moveset for Ho-Oh, but that decision depends on where you need it to fit into your teams. It's a solid mon that can be good at a lot of things but is the best at nothing.

I’d save the golden raspberries and use them to catch mons to save on balls.

So those are your best Groudons and Kyogres and you don't have any others powered up yet? If so, transfer your rare candy them because they're worth powering up at some point even with the IVs being not that great. Ho-Oh on the other hand isn't a good investment for the long term.

Bag space and Pokémon storage are some of the best things to buy in this game. Bag space means you can stock up hundreds of balls when you visit a place with lots of stops, and then you won’t need to ration them.

Pokémon space let’s you do things like save hundreds of pidgeys for mass evolves when double xp is active.