Soft level cap has been pretty common in difficulty hacks. In Insurgence you only earn 1 experience, in Nameless Red you don't get any experience at all and in Reborn Pokemon disobey you. Reborn has the most ''organic'' and ''canon'' system, albeit the most annoying one if you're not expecting it but it's nowhere as bad as you make it sound.
A level cap is needed to ensure fair difficulty, if you make the gym leader's Pokes too high level then you're forced to grind and that's actually bad game design aka time=win instead of skill=win.
I'm sorry to say that if you usually resort to grinding to brute-force your way into games, it won't work on Reborn.
As I said in my post: Ninjask (Speed Boost) with Magical Seed, Substitute, Swords Dance, Baton Pass combined with a Krookodile (Moxie) with Magical Seed, Earthquake, Crunch.
Open fight with Sub, then SD, then Sub again. Baton Pass onto Krookodile who sweeps with EQ/Crunch.
In my latest run I used Ninjask with Sub+Sword Dance+Baton Pass, get a few Speed Boosts with its ability and then Baton Pass'd to a Krokodile with Moxie and a field Seed as its item.
90% sure this website isn't affiliated with the Insurgence team, their real website is https://p-insurgence.com/
That website looks created by someone who wants to make easy ad money and/or make you download malware.
When I beat Solaris in ep 15, I found that his Garchomp AI would use Earthquake on a pokemon with Air Balloon. So I equipped a ground-weak pokemon with one and all his EQs missed, ggez. My initial strategy was to simply use Intimidate spam by switching between pokes with Air Balloons then end up Burn'ing him to death.