I guess one way around it is for an exchange to bank with a building society that is not on faster payments but uses the slower BACS system (which takes three days).
If that was possible we'd already have it. Probably the lowliest single granny credit union has been queried by crypto businesses and she must've told them to go fuck themselves.
Even if one institution got in they'd be shunned by everyone else and would have to give it up.
What's needed is clear and proper regulation from the government. No bank wants to have to interpret woolly statements only to be nailed to the wall later. Easier to say no to everything.
You are wrong, because your fiat is US it does not means that other people doesn't feel the same when they are approaching to another psycho barrier.
1 million yen is a bigger deal in one of the biggest markets. They didn't seem to hang around too long before breaking through.