Moving from Evernote to Onenote - it seems like I really need to put everything in one huge Onenote

I posted this to answers.microsoft.com, but haven't gotten much back:

I'm moving from Evernote to Onenote.  I organized everything on the EN side first (because moving things around is drag-and-drop in EN, and a royal-pain-in-the-**** in Onenote).

I knew once I got things over to Onenote (using the MS conversion tool), I'd have to move things around to get my organization back.  I don't see why the converter can't do this for me (it's a trivial algorithm), but, still, I knew this going in.

The ugly surprise is that it appears you have to "open" EVERY NOTEBOOK ON EVERY DEVICE to get access to it!  I have, like 50 notebooks in EN, about 40 of which I moved over.  On W7 (Onenote 2016) and Android, these have to be opened ONE-AT-A-TEDIOUS-TIME!  On every device.  The W10 version claims to be able to open many at once, but it doesn't show all my notebooks (no, this isn't a user account problem - I only have one, and I can see all my notebooks on onenote.com - it just plain doesn't work for more than about 15 notebooks).

I'm not going to go through that on every device I use.  I'll be at it until Doomsday.

How do other people deal with this?  I'm wondering whether I need to throw everything into one giant Onenote monster notebook, then put the real notebooks in as "Section Groups".

But, then, I went to Onenote.com because I wanted to search all my notes without spending ages opening all the notebooks, only to find that the search box labeled, "Search my notebooks" does nothing of the sort - it searches only the notebook TITLES.  I found an answers.microsoft.com posting on this dating from 2016, so apparently it isn't considered a bug.

But having the ability to search only the titles implies that people regularly have enough notebooks to make this non-trivial.  But, then, how do they deal with the open-one-at-a-tedious-time problem?

I'm confused.  There are millions of people using this tool, and it's been out for many years.  So, this can't just be growing pains.  How do people use this tool?  One notebook (but, then, why would you want to search the titles), or many (but, then, how do you deal with the opening problem)?

[For those not familiar with Evernote - every note and every notebook is available all the time on every device without user intervention.  I suppose the Onenote structure might be useful to save space on specific devices, but it would make a lot more sense to exclude notebooks on specific space-constrained device rather than include them everywhere else.  Give that Onenote already has user and work accounts, what purpose does this structure serve?   Why would I NOT want access to all my notebooks all the time??]