The right way to do this is open the project in GarageBand and export each track as its own audio file. Then you can import the audio files into a PC-based multichannel audio editor and continue working.
Failing that, though, notice that the GarageBand project is a folder, and inside the folder there is a “Media” folder that contains the individual audio ...
Yes, this is possible. It's unfortunately not straight-forward, nor will it be cheap, but it is do-able - except not via USB.
I can give you one example of having done this myself, but you're not going to like the answer - becuase it's particularly pricey - but remember, this is just one example.
Sound Devices 970, MADI/DANTE recorder.
RME MadiFACE in the ...
I've never heard of the 'sticky tape' phenomenon affecting anything other than specific Ampex 456 tape made during the 80s… & boy, have I baked some of those over the years ;-)
Old cassettes may shed a little, but I don't think they should be sticky. I'd play one track at a time & clean the heads before each track.
Unless your heads are so far out ...
I play all kinds of tapes from the 70-90 no issues here. I think they will still work flawlessly. Tapes are build like tanks :)
You definetely won't rip them off at the end. I tried to rip one by Hand. No chance.
The speed may vary (and actually you may even see differences between units of the same model). If you know the tuning, chords etc you can always go through a computer and resample if you want pitch to be perfect.