I was only tired because it was always an opponent Ash had to beat, and there were several (marketing) reasons he never got to own one despite the many instances that were perfect. Sadly, each instance was someone else owning it that he had to fight. I wasn't amused when one was forced onto Kukui because then it got silly.
I feel a similar way towards Charizard, it's my favorite pokemon but in the anime, the only Charizard I really care about is Ash's, so yeah seeing other random ones can be annoying.
Reminds me of how during unnova I kept getting annoyed by the amount of trainers who we saw had tranquils, with better movesets than what Ash's had at that, and made me wonder if he should've even gotten one.
Him finally getting a riolu of his own is what makes me interested in it, by all accounts I agree he should've gotten one back during gen 4, but given how this current series is going It's fine.
Just wait for th Gen 4 remakes and GMAX Lucario
i'd personally rather they just go back to mega's, after all I could only see them restructuring the battle zone as a wild area to accomadate the new gimmick (I seriously doubt they'd tamper with sinnoh's mainland) and even then we know in the anime Eternatus isn't locked down to Galar like in the games, but in sword and shield it's established that the current gimmick can only be done in galar due to it's influence over the region.
If potential sinnoh remakes got access to the feature, it could lead to further credence of it being used anywhere in the anime, and I know quite a few people don't like galar getting cheated over as it is.