What brands were you having issues with? I’ve been really lucky with cassettes, I tended to buy Japanese stuff (TDK, Maxell, That’s) and they all seem fine without any shedding. With open reel I’ve certainly had issues with Ampex, Scotch (Ampex), Radio Shack (Ampex) etc, but again the Japanese stuff seems fine. I actually ended up baking an old Ampex master which got it to play well enough to digitise it. The food dehumidifier could be a really good option here if it is big enough to take a 7” reel!
I think even the cheapest kind I've got would indeed take a 7inch reel - but I am talking, in terms of direct experience, only about small format:
I hoovered up a load of pre-recorded (commercial releases) from ebay: from the late '60s (a 'Pepper' - which actually sounded great when it played ok - didn't heat that one, although I still have it, and should give it a go) through to the late 80s (a few 90s I think).
So - not the higher quality tapes for home-recording which I assume you're referring to ... ?
I made a post in another thread a while back - I'm not sure what I'm talking about is sticky shed syndrome as per Open Reel tapes as such - although the sound issues, and 'cure' are effectively the same. So it's still linked to shedding - just with small format tapes, it's not so dramatically obvious and ... er ... sticky.
I gave up on it due to 'costs' ('tric and enviro), and also the tedium factor tbh (mostly that) - and that was before the huge s**t-fest we're in now.
But honestly - I can only say it worked for me, short-term at least. To begin with I was blaming the decks (all picked up used from ebay / cash-convertors etc).
It's probable that they did need servicing and thus may have been compounding the problem (in terms of 'slow-down' anyway), but the heating (round about 60 degrees for 8hrs or so, as per tape-heads advice) did get all the ones I tried playing.