This was the case during my first playthrough, where I caught every new Pokemon I saw.Aggressively disagree that ,even before the EXP Charm was added, SWSH had a pro-exp share level curve.
I had to go out of my way multiple times during SWSH to avoid just instantly out leveling the competition and leaving them in the dust. You just earn too much EXP in aggregate unless yo ustart ignoring pokemon and eventually ignoring trainers where possible and even then it is staggering how quickly you catch up.
On my second playthrough though, I caught almost my entire party near the beginning of the game & only got EXP from all the trainer fights on each route. I actually was starting to fall behind the level curve around the 4th gym (though I got back on track by the 5th one) . I think Sword and Shield's level curve was designed with this style of play in mind.
Still, I think the decision to have WILD POKEMON be at a higher levels then some of the trainers you fight in later routes to be very weird. My guess is this was done so that players would have an incentive using these mons over the ones they caught in the Wild Area.