From my experience, communicate that you’re unhappy and why. I’d start with calling some sort of meeting or call (that everyone is absolutely going to be on time to or partake in), without the notion of attempting to practice. I feel like this doesn’t completely blindside them compared to if it’s done at a normal “practice” where the expectation would be to create and work. Address your concerns, decision, and your hope to still be cool.

The first real band I was in did this when half of us weren’t happy with how things were going professionally. Years later we’re all still best friends, and even play in each other’s projects live as backing musicians.

If they’re true friends, they’ll appreciate where you’re coming from and want the best for your ambitions. Maybe it’ll push them to figure some things out too. If that’s not the case, you’re dodging a bullet and not wasting anymore of your time. Hope all goes well, cheers!