GS Mini has a solid top, so is also vulnerable to low humidity issues. Your laminated top Yamaha is a good candidate. Some re-fret work and a good setup - part of the same process - might be the best bet, unless you are looking for something different. You can probably get the first 5-7 frets done for a reasonable price (we cannot discuss pricing here, even for something like that). If a re-fret it is not worth doing, maybe look for an all laminate replacement such as another Yamaha, Seagull, Recording King or something similar. The suggestion for an entry level used Ovation is good too, if they work for you.
When I lived in Alaska and struggled to get the indoor RH up to 20% in the winter, our solution was a Rainsong carbon fiber guitar, which has become my favorite in part because it can live on a wall hanger. Not cheap, but very nice. BTW, I rarely see any CF instrument even used for less than two GS Mini's. There are no "inexpensive" CF guitars.