Master Duel is a better game
As someone who has been playing Magic for the better part of 15 years, I can confidently say that Magic Arena has ruined any semblance of fun in Magic the Gathering I once felt. The economy is trash, the algorithm used to determine rng is flawed, the game modes are limited and unfun and the game itself which thrives on being a social experience is ruined by having faceless opponents with no interaction. Magic Arena is by far the most soulless experience I've had with any online tcg, ever. So many times I boot up Arena after not having touched it for months only to be reminded "Oh yeah, that's why I stopped playing this game". Devs have long since given up on trying to make Arena anything worthwhile other than trying to squeeze out any last semblance of change from this dying client and it really shows.
Now as a longtime MTG player, when Yugioh's Master Duel came out it's like they did everything that Arena should have done and it clearly is thriving because of it. A better economy so your cards aren't inherently wasted if you open garbage rares that you don't need. Actual competitive events and season passes that don't rob you for trash rewards. Yugioh at a competitive level is so much more focused than what MTG is in a 1v1 setting as well and not having to deal with a flawed, outdated mana system is what allows newer TCGs to shine. So yeah, I have nothing left to do with Arena because of how utterly trash the game is, how unfocused the dev team is with handling their own game and how flawed an old game like MTG can be when it comes to a competitive 1v1 environment. Seriously, who loves losing game after game because you can't even draw a land to play your spells?