Cooking system for a group of 4?

While the Brunton remote adapter isn’t available, there is a knockoff sold on eBay (which I know nothing about, but it looks very similar.)

The cheap Chinese adaptor leaks badly depending on who made it and only works on the butane spray cans The Brunton unit works on threaded Lindal valve canisters

I used a no-name Chinese remote successfully for a few weeks, but the threading and gasket quickly failed.  It was also unreasonably heavy.  The only reason I still have it is because it’s a rather nice design, and I would like to replicate it in a lighter material with quality components.  But yeah, be careful with things that are made from chineseium.

This guy is obsessed with stoves. I love watching him boil water. You might find some ideas on his channel.

If it were me, I’d just use a single remote stove with a good BTU rating, the properly sized single pot, like 1.5-2L (unless you are cooking multiple food types at the same time, or need food really fast? If so, then you’d need more than one stove), and a proper Ti windscreen for efficiency. Unless you are wanting redundant systems, the single cookset is going to be simplest. As others say, find the widest pot for the volume you want, it will maximize the flame’s contact with the pot base.

For a one stove setup I would go with a remote stove to use bigger pots. If you have 4 people who can carry typical loads you could take the smaller stove to and everybody can haul some fuel too.

I was surprised how much water was needed when camping with 4. It seemed that someone always needed hot water. More was needed for cleanup too

I use a rather heavy Primus multi fuel remote model in canister mode for car camping and really appreciate the stability.

A combination of pre-soaking and a really good cozy might help.
Naturally you need to balance fuel savings against the extra carried weight of the containers and the cozy weight.