So, to explain my thinking, as you said I wanted to more or less clear the sides before moving to the top. I also wanted to make sure I did a mix of all activities with "focus" on the Gyms. Since the game prompts you to do both a Gym and Titan first, since there was more Gyms I challenged Katy first (sorry Katy) and then went to take on the Titan (followed by Brassius). Well, being Mela is RIGHT there, and thinking "well, since they heavily advertised her and only her, she's probably the first intended Star boss", I challenged her 4th. Now, that's not too bad, since I was exploring as much as I could I was actually quite well Leveled plus had plenty of Pokemon to handle Fire-types so I got through without incident. Deciding to "clear out" the bottom east side, and the second major city seemed like an interesting location, I challenged Iono.
With that done, I figured I'll mirror my victories and flew to the west side. While figuring out how to get to that strange out-of-the-way bottom Gym the trigger for the Flying Titan happened and decided to take care of that as throwing boulders is just rude (plus wanted to see what the windmills had to offer, happy we were allowed to climb up them). Anyway, after failing to jump a simple ledge to enter the intended way to Alfornada, I found the bottom way... and experienced my first Level spike. Suddenly all the Pokemon were Titans and all the Trainers were Gym Leaders. Now, I could have decided to come back later with higher levels, but the game didn't expect somthing: me being too stubborn to know better. So, pretty much ignoring ALL battles, I managed to Alfornada to at least save at the Pokemon Center. Now, with it on the map I could have gone to Cascarrafa to see if Levels were better there... BUT now with a Pokemon Center nearby and my Pokemon not being TOO underlevel I decided to first beat as many trainers needed to get the League Rep's reward. After doing that, well, I could at least see how the Gym Test is (hi Dendra, are we battling you? Oh, no, just a vibe check, got it). Okay, so that wasn't hard... eh, I'll challenge Tulip, got PLENTY of potions plus my Skeledirge... OF course her Psychics would be packing Crunch and Shadow Ball; power on through!
Well, I just defeated the 7th Gym Leader as my 4th (and overall the 14th Badge as my 7th), at this point I realized the Levels are set so wondering if I'm not overleveled by the game's standards. I was. Cleared Kofu, Paradox Donphan Titan, and Larry (surprised I did Kofu and Larry technically in order, though that only makes the Paradox Donphan Titan being a couple Badges above them odd) so the entire south was done! With a giant lake and snowy mountain directly north, figured now would be a good time to fly back to the other side and take on the "quarry" next and its Steel Titan. Got through Atticus so now all that was left was the 2 Gyms, 2 Star, and 1 Titan. Well, obviously a Gym would be next and since they advertised Grusha that probably means the Ghost Gym is last, RIGHT. Well, might as well have been as, spoiler, I had a more tougher time with Rhyme than Grusha, at least some of her Pokemon was able to take a hit (though tbf to Grusha, Torch Song is OP).
I went for Eri next (and that was quite a challenge, didn't know whether it was a Level spike or just cause Fighting-types hit hard... turns out she was meant to be the last Badge you get for some reason). Decided I was good to take on the last Dragon Titan and fully upgrade my 'Raidon... oh, and I guess finish the Path of Legends (though I didn't battle Arven until after I did the Pokemon League & Team Star as I learned about the final story and how doing Path of Legends last better rolls into it). Wanting to finish the Gyms last, I defeated Ortega where I learned not only was he weaker than Eri but also had the most plot relevant story and left confused why they would do that. Well, Rhyme was supposed to the 6th Gym/12th Badge and I've gotten every other, so though the battle was fun just because it was a Double Battle which was a nice change, it was a done deal.
Hence, my Treasure Hunt route, showing just how ludicrous the intended route is supposed to be while also showing with enough exploration it doesn't matter. *Shaky thumbs up?*