Recently made the switch from Motorola to Samsung devices, and all-in-all I'm very satisfied with the change.
The first time I've used Motorola I loved the all-clean Android option and refused to use personalized UI's at all.
Then Motorola ruined the experience with a low end Moto C device that made me hate the brand as it wasn't able to keep the RTC running properly, the clock and alarms weren't working completely.
Samsung blinked its eyes on me and did the switch and I'm using an A51 with pure joy with plans on getting a Samsung high-end cell phone soon.
Samsung imposing rules on their certified repair shops is something I would do if I want to ensure customers get the best of my brand, including repair quality and warranty.
While most people see their contract requirements as a hurdle in their way, I see it as a plus for the brand and their products.
But yes, there are some parts of the "contract" that turn the red lights on. Like requesting to report if the customer used third party repair parts on their devices.
The most important part of this all is the certified part of the argument, if you want to be certified, you must comply to certain rules or else, do third party repairs.
We all know many third party repair shops use (re-use actually) second hand parts and sell them as new, or third party repair parts as originals (not everyone does it but you know the drill), that's something that hurt customers' pockets and brand credibility.