My group does discord, we play on VTTs so built in voice chat was a requirement. You really don't need to engage with any features you don't want/need to. If you're the only DM you can be the server owner and leave everyone else a default user.

For a more FOSS answer I think Matrix would cover basically everything that discord does. I haven't used it that extensively but it seems to be the best discord alternative when dealing with larger groups where you may want several text channels.

Discord. I got a channel for absentees, one for scheduling, one for talking, one for roleplaying, and of course vocal and webcam features. Also uses a bot for music on it for free. You can add how many channels you want for : lore, maps, links, memes, etc

We use discord. My group is actually about 4 groups connected together with overlapping players, so it's a place we can all congregate virtually. We have a channel for scheduling, ones for in-game content, and some for just messing around.

My club is old school and has a forum. It's still work quite well at announcing new games, and tracking ongoing games.

When I GM, I post a reminder 2-3 days before the session, but try to set up campaign at fixed dates

I've got 4 groups.

Groups 1 and 2 are small groups made of friends and we handle everything over text. We do tend to have a lot of "hey, are we playing today?" texts on the day of.

Group 3 started as a work game and has a larger group with less consistency of who shows up week to week. We use discord. Creating events, hosting lore, and places to stash special/homebrew rules is nice.

Group 4 is a west marches-ish game with about 10 players. Discord for that also, though once a group is set for a couple sessions we switch from the discord channel to a group message for communication.

I've used Teams in the past as well but I find discord to be better for managing the various things I need to organize a game.

Steam Friends and Discord.

WhatsApp to coordinate.
Discord for voice chat and sharing links etc.
Foundry for play.
Miro for "clue board" when playing investigative games.