In that scenario it looks like members must coordinate to identify the highest committed transaction (identifying the list of valid members) and then bootstrap from that member?
Stateful Sets were designed to standardize two hard problems: being able to identify all the valid members (pods identified by number that are running at most once on any node) and give admins the button to decide a member was never coming back (the force delete pod / force delete pv action). That was true black magic before - everyone did it their own way. So we worked with the ecosystem to enable vendors/communities/individuals to map those primitives into specific solutions, but did it somewhat deliberately as “we have to build this together”.
What I think the gap has been is that there is significant friction in between the three realms of expertise - knowing what kube is providing, knowing how to map that to a specific problem like translating the Galera runbook into operator/script logic, and then communicating that to the teams that will be accountable for reacting. Vendors have incentives to make you pay for that expertise (or may not have it), large organizations hire people to provide it (most large db on kube deployments are also large tech companies), and in between you have a lot of uncertainty and knowledge gaps that doesn’t necessarily transfer, and that is what drives “Kube isn’t great for stateful”.
It’s ironic to me because StatefulSets were intended to take advantage of those incentives to help the ecosystem scale, and the result is “worse is better” in that many more people can do state on HA DBs than were successful on VMs or metal, but it doesn’t mean they’re completely successful and when people hit the rough edges it hurts. We can do better (that’s partially my day job), but there is a lot of pain people have taken so far that was probably unnecessary. You should use managed DBs if you can - and when you don’t, Kube should be the best alternative it can be (which isn’t far - many DB SaaS uses some kube), and that’s what we need to focus on.