Natural Selection 2 is still active. 2 non-symetric teams of 7-10 players each have a commander who plays RTS. The rest are marines building resource towers, upgrade buildings, scanners, ammo depots that commander places. Commander may direct people to speccific tasks, but usually people just know to for groups of 2/3 and be effective. Commander then places building plans, and can heal/drop ammo/scan (and more) for marines on the field. Aliens are a little more individualists, and geberally only 1/2 players help make building happen faster.
The map design is amazing, game runs and looks great. Highly reccomend
Arma 3 is one possible implementation of this.
BUT, it requires to download and install mods, find (a lot) of people to play with.
The way it's made requires a lot of dedication -> gathering everyone, organisation to communicate can be tricky particularly if you want realistic kind of comms: teamspeak is still required (I don't think there's a realistic mod for Arma 3 compatible with Discord).
Nevertheless, Arma 3 has everything you need:
Big maps (open world)
An actual map (I am talking about the paper/GPS thing) -> with actual elevation information on it, etc.
Complex strategies and tactics possibilities
Communications
Vehicles: helicopters, tanks, cars, trucks, planes, boats, etc. etc.
A very WIDE set of weapons of all kinds: turrets, firearms, launchers, mortars, etc. etc.
All this adds up to the need of coordination, planning, preparing strategies, primary objectives, secondary objectives, backup plans, backup plans for your backup plans, etc.
There are two games that come to mind that are/were like this:
1) Total War series — it's not FPS per se but there is the idea of managing the macro situation (resources, where armies are, developing cities, etc.) and then when you actually attack another army or lay seige, you have more of a tactical view where you direct the action.
2) The original Rainbow Six (and maybe some of its immediate sequels). You would plan out exactly what you want every one of your special ops guys to do (e.g., when I give the signal throw a flashbang into this room) and then you get to play as one of them. Not sure if anyone has replicated this yet!
I feel like such game would be hard to balance, because everyone would want to be the boss. And even then, you'd need some very good ideas to provide compelling gameplay for both the commander and the commanded.
Actually it's kind of the opposite. No one wants to be the boss! So you either get a reluctant commander, a person who knows what they are doing and really want to command, or a person who doesn't and has to be brought up to speed through in-game voip while playing.
Honestly, NS and NS2 the commander was a fun position. You play to upgrade your units, grab resource nodes, and expand influence, while trying to direct non-compliant troops. (Really throws in a wrench to your RTS when you can't get your soldiers to do something you need). Another aspect is in the smaller team dynamic of NS, one or two good troopers can have an outsized effect on enabling the commanders gameplay.
Empire mod gets around this by having larger teams (15+ vs 15+) with vehicles, upgrades, weapon customization, tech trees, so it really plays like a war where you need to counter what the enemy brings to the field in terms of tech.
Hell Let Loose is an excellent game! A great balance of strategy and action, even as a grunt if you work with your squad there's a lot of strategy and tactics.
The map design is amazing, game runs and looks great. Highly reccomend