I definitely don't want to be the one responsible for you not getting your dream trailer! Look, the Classic is really nice with cool features. It's also a more complex piece and that comes with issues too. The GT is a clean modern design inside and is more basic in some respects but it appeals to us. It's all
very subjective. The big issue is size; if you can go all the places you want to go with a 30' trailer then the Classic is your obvious choice. The simple truth is it didn't work for us. YMMV.
As you've seen, resale varies widely; probably based more on condition and market forces than mileage. Our 2018 new listed $20K less than the 2021 does and we got a nice discount. Still, we lost about $35K all together on the trade in: could have done better if we'd sold privately but didn't want the hassle. My advice would be to try and pick the right trailer the first time.
Good luck!