I 1000% depend on time stop and not having this in co-op is shocking and nerve-rattling. I never want to waste the time organizing. OK I never want to anyway but now I have like the bestest excuse not to ever! And doing any kind of timed thing like a Skull Cavern run or the Deep Sea Fishing Expedition end in about half the time.
And mostly I just need that timestop to think. That takes me a long time and thinking of what I'm doing is like half my day. Not to mention Fishing! It takes me forever to hook some Fish and that means wasting in-game hours just reeling in that stoopit Eel!
Your best bet would be to install a time slowing mod (hmmm those are quite popular, how could that be?) but only if you're on PC/Mac/Linux. And maybe Android, I'm never sure there. But not on iOS or Console though, which is where a lot of players are.