The real question is why on Earth (or space) do you have so much gear that I am 90% sure you don't use. I keep a few God rolls of items I don't use too in the event they become buffed and meta changes but I can't imagine running out of vault space tbh. Sounds like you kept alot of junk gear tbh.

just a few tips, don't put shaders, mods sparrows, ships, ornaments or ghosts in your vault. all those can be reacquired from collections or just become unlocked. You only need to unlock a shader once then you can buy them at will from collections when you actually want them. Sparrows and ghosts can be repurchased from collections as well as many times as you want until you get the perks you want with them. No need to save them. As for armor, you probably can use your 9 character spaces on each armor type to store the ones you use most like exotics. I don't fully understand armor 2.0 but i think you can swap out perk mods so you don't really need a ton of them saved in the vault anymore if i understand that correctly? That leaves you 500 spaces for weapons with great rolls. It'd be great if they added more space but don't hold your breath.