If I tell you to "take out the trash" I've asked you to do one thing. It's one cohesive idea. Does that mean it can't be decomposed into more things? No.
Everything can be decomposed into more things. If I tell you this function should do one thing I'm not telling you it should manipulate only one trash bag or only one quantum quark. I'm telling you if a function named "take out the trash" also implements "bring in the mail" it's going to surprise and annoy me.
Now you can argue that it makes sense to bring in the mail when you take out the trash. That's fine. Where you went wrong was the name.
"Do your chores" fits, but it's jarring. It's a grab bag that doesn't tell you exactly what is inside. But it does tell you what should and shouldn't be inside the function. It's different than before because this is a higher level of abstraction. That's why this is still one thing.
You could argue that it's doing two things. But I could argue that taking out the trash involves walking, tying up bags, and opening doors. There is no thing that is one thing. But there are things. Clear things. Things that say these things don't belong in this thing. Such things have cohesive names. Names are exactly the limiting factor here.
"Deal with trash and mail" is bad mostly because it does tell you exactly what is inside. It's telling you implementation details. It has not taken any responsibility for communicating the single thing it exists for. It's just telling you what it contains.
Given this what should you find when you look inside "do your chores"?
If it's a list of containers to open, items to remove, and locations to carry them to then you've wasted two good names and a useful level of abstraction. Please don't throw away "take out the trash" and "bring in the mail" just because "do your chores" exists.
If you want to follow "Do one thing" step back from what the function does and ask what it's for. What does someone calling it really need to know? What details don't they need to know? Can you name it something that will mean something to them?
That's the one thing. Sure you can cram every detail into the name but it's better if the name centered around one single idea of what the function is about. Not every little thing it does.