25 hours and you're three gyms in? Pretty sure I was done at that point. Guess that's why they call you SLOWnenberg :p
I don't get why people somewhat race through games. Seems like there is a competition to say how quickly you beat a game and then complain it wasn't very long. Like I said I'm not trying to play slow, just taking the game as is. I can easily see how I could play through the game way faster. For example, one small area I spent 2 hours in and afterwards I was like man if it just walked through it, fought a couple pokemon but mostly ignored them, and beat the trainers that woulda been like 30 minutes at most, but there were a bunch of new pokemon readily available in that area so I tried to capture them (doing my best to not fight the same ones over and over) and then would have to run back to the nearby town a few times to restore my pokemon since I'm out there battling pokemon and trainers, so just playing the game like it is meant to be played and not just quickly walking through takes a lot longer than 25 hours.
So I can absolutely tell its very possible to beat the game in 25 hours or less like you did, but that'd require me to just walk through the game and not explore things or talk to everyone or try to catch the pokemon I see. Racing through the game in 25 hours I'd feel like I barely got the experience. Even at this rate it feels like I am not properly experiencing parts of the game and I would have to slow down a bit to get the full experience. Like I've only bothered to go into one of the little energy dynamax things whatever they're called in the wild area - that's one in almost 25 hours, so I've basically completely ignored those so far. And I haven't done any online features, I don't even know what online multiplayer features there are. It just seems like a misrepresentation of the game when people say oh it only lasted 20-25 hours or whatever when that is only if you want to beat it fast and don't take your time to settle into the game. It's like saying BotW isn't a long game cuz you don't HAVE to explore most of the map. Or like Mario Odyssey I think I beat it in 25-30 hours, and I could have totally beat it faster, but there was no reason to do the bare minimum to get to the end, and I doubled my play length in Odyssey so far its at over 55 hours and there's still stuff I want to do in the game.
Basically you get what you put into Pokemon Sw/Sh in terms of game length. If you want to get through the game, sure its totally beatable in 25 hours or less, but if you want to get the full experience that is offered that could easily be 40, 50, 60, 70 hours or more. To me its looking like it'll be 50-60 hours to beat the game, knowing that I ignored some parts of the experience, which is fine cuz its not my favorite game ever and I've got lots of other games I want to play.