I think yours is an interesting question, and its worth exploring for the sake of figuring out the important slots in a bag vs the ones that can be filled by practically anything, or nothing at all.
Here's how I like to think of my short game:
Putting putter - my putting mold for in the circle and out
Putting putter thrower - I like to take a duplicate of my putting putter, usually in a softer plastic in baseline, and bag that as well for throwing and upshots. At this moment, this is a 4S Wizard. Usually a 2S in the warmer months. In theory, this one could be a little beat up to use on longer putts, and I could end up with a bit of a cycle.
Forehand upshot disc - Assuming my putting putter is a mold I am not a fan of FHing, I'll carve out a slot specifically for a disc which handles well on shorter FH shots. Think Zone, Harp, Rhyno, whatever. The important thing here though is that I've identified that I need something pretty niche to fill this slot, as opposed to simply bagging another of my putting mold in premium plastic or the like. When I was putting with DX Rhynos though, this slot was filled with a champ rhyno.
From there, the rest of my bag is largely structured around molds that, through experience, I've found that I want to lean on.
It's a buzzz, then essentially an overstable buzzz and an understable buzzz (wasp and vertex or tursas).
It's an FD, and so on.
It helps to have the experience of trying a bunch of molds to figure out what clicks, or simply throwing a particular mold a lot and deciding to stick with it. From there, you just fill things out to the degree you are comfortable with.
Ideally, throw your workhorses in a plastic which breaks in quickly so you can try cycling. Then fill your bag out with premium plastic bookends - like I could throw X buzzzes and the OS and US complementary discs in Z plastic. If that doesn't work out, don't be afraid of mold count in your bag, just find something that feels and performs similarly to your workhorse, but more or less stable. This forum is your friend for that - hundreds of "suggest an overstable Buzzz" threads and 10x the suggestions (the answer by the way is Wasp).