You don’t. You play the game, and conduits will eventually drop. By the time you unlock enough conduit slots, you’ll pretty much have the conduits you need. Then it’s just upgrading them, which comes naturally with playing the game as you normally would.
You don’t specifically grind conduits - you can’t, they don’t have a fixed drop location anyway. You play the game, and conduits drop.
You get renown from doing your covenant campaign, and for callings, which usually can be completed by doing the things you’d do anyway. You won’t even notice when you cap your weekly renown.
You don’t get more gear in the vault for running more m+. You get more options, but still a single choice. Besides, if you wanted to gear up, you’d run more than 1 m+ anyway. Unless of course you’re already decked out in m+15 gear, and the vault is your only upgrade, but… that’s going to take a good while.
Oh my, an hour a week. Such burden.
The Maw is actually daily, not weekly. Now this part is grindy, but the only grindy PvE part in your entire list. However, for an alt, you don’t need sockets. It’s okay if your alt is not as powerful as your main - then it’d be a second main, not an alt. So if you go to the maw once a week for 30 minutes on the alt, that’s still going to be okay. You will be able to participate in raids, m+, and pvp on your alt. Perhaps not at the level as your main, but the difference will not be nearly as huge as in BfA.
Also keep in mind, that all but one of the things you listed is weekly, whereas in BfA, most grinds were daily, or didn’t have catchup mechanisms. That’s a huge difference.
Mind you, keeping a second main up to date will be a whole lot easier too, because half the things you need, you get by just playing the game as you would, without having to go out of your way to grind them.