Autorecovered & xlsb workbooks

[JenniferMurphy]

Ever since I "upgraded" (and I use that term sarcastically, pejoratively, and a few other terms I can't use here) to Win 11 and Office 365, I frequently run into a "autorecovery" situation that I never remember encountering before on Win 10 or Office 2017. It only happens with Excel files, usually overnight, and usually after I have had several open for more than a day. I go to work with one of the open workbooks, and I see this:

The filetype is "xlsb".

If I click on File > Info, the option to open the file location is missing. This is probably because this "AutoRecovery" file has not been saved.

If I try to save (Ctrl+s), I see this:

It looks (to me) like it is going to be saved in a Roaming folder and the filetype will be xlsx.

Questions about this condition:

1. Why is this happening and what do I need to do to stop it?
2. How should I handle this when it happens. I currently have 6 workbooks open, all with this condition.
3. How do I make sure that I have the most current version with any and all changes I might have made since the last save.

Questions about xlsb files:

1. Why are the AutoRecovery files given the filetype xlsb?
2. I looked up xlsb. It says that it is a "binary workbook file". It also says that binary files can be loaded much faster and this is useful for large workbooks. I have a couple of large workbooks. Should I change them to xlsb? If so, how do I go about that?