1. Depends on the manager. People tend to go all "control freak" when they feel out of control in some other way. So they want to do the thing they KNOW how to do, to feel competent. \
   If you can start from that point of view (whether it's specifically true right now) that your manager realizes they're in over their head, you might be able to coach them into how to manage you. \
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   For example, "I am working rn on x and y, to get \[thing\] done by \[milestone\]. You want me to do z. That is going to impact the timeline of x and y -- even if I work late to get it done, because I'll be more tired then the quality may suffer. Is that the prioritization you prefer? Z first, then x, then y? \
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   In other words: their job is to prioritize and remove blockers/find resources. If they're not doing that -- if they're seagulling (fly in and \*\*\*\*) -- then nudge them towards prioritization and blocker removal anyway. \
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   Also, and this may sound super manipulative, but it's really not: when they do a good job doing THEIR job, give them approval! Thank them for organizing, removing blockers, finding resources, aligning stakeholders so your project has support, etc.
2. Not sustainable long term, and whether you personally can endure it really depends on whether this hooks into your own issues, or whether you can separate it out and do good work, despite this noise. I would have a very rough time, and I'm an oldster. But I know people who truly don't care at all, and just roll with it.
3. "Most" isn't really relevant; I think you're looking for "enough." Enough so that you can specifically search for a new manager where you ask behavioral interview questions such as "you know your direct has a lot on their plate, but your manager just asked you a question, and you want to get the answer to them. What do you do?" (Follow up: "What do you do if your manager does that frequently?")