Still looking? I'm in a casual guild, we have some members at around 10M GP, average GP is closer to 4M. We do DS TBs, and once a month do ROTE (not getting Reva shards right now). Speeder Bike raid usually at the 36M crate.
It's definitely laid back. A friendly guild, no requirements really, just participate as you can, no Discord or anything. We use the in-app chat a bit, but it's up to you.
The main reason I stay, even though it isn't the highest resource-producing guild I could probably join, is that it really is casual. If you need a day or two off, no one will think anything of it. People seem nice. It's good for taking things easier, while still doing more advanced game modes, and having guild members who can support that.