Is Boltz (and Aqua, for that matter) exposed to pressure from the US government in terms of being forced or pressured to shut down access to US residents (like Wallet of Satoshi and Phoenix did)?

That's happened with a lot of wallets in the past year or so.

From my understanding there's also an argument against Liquid, which goes along the line of "it's a side chain which will eventually have the same problems as bitcoin, as transaction volume picks up". I'm not sure when that will happen, but maybe by then there will be other solutions.

So far, I've been pretty satisfied with stashing in Aqua until the stash gets large enough, and then swapping to on-chain. It seems to always work.

The same can't be said for using self-custodial lightning. Maybe I'm an idiot, but I've had one problem and hassle and headache after another. And every problem requires tons of work, what with contacting developers or going to telegram groups to try to figure out how to solve it. It's absolutely not easy at all. I haven't lost sats so far, but it feels like it's come close a couple times. In my opinion, it's nowhere near close to having normal people use it - it's only for highly technical, highly motivated people who are able to spend a lot of time on it, as a project.

Maybe better self-custodial lightning tools are coming along (maybe Alby Hub?) that will make it a lot easier for people to be an "Uncle Jim". That seems far off, though. And also...how realistic is that? I personally wouldn't want to undertake a responsibility like that except for very close family.