(tldr: I want to reinstall elementaryOS fresh on the same partition, without damaging my Windows partition or messing up the ability to dual-boot. What do I do?)
I've damaged my elementaryOS 5.1 Hera installation, by trying to solve a problem. (It still boots, but it's unusable; among other things, the mouse is frozen.) The details aren't important, since what I did didn't solve my original problem anyway. So rather than debugging, it's simpler to wipe the elementaryOS partitions and reinstall from USB. (I have no data at risk in elementaryOS.)
This is an ASUS Zenbook and I have Windows 10 on another partition. When I turn on the machine, I get a Grub window with (elementary, elementary options, Windows Boot Manager) as my choices.
What is the process for reinstalling fresh? Do I simply (from within Windows) erase and reformat the three (as I recall) partitions used by elementary, then boot up from the install USB and install as usual (via the "Something else" option)? Or is there something else I have to do?