Black Desert is one of the most popular MMORPGs available on all platforms including PC and console. The mobile version looks and feels like a console game.
While the game has a lot of feedback on micro-transactions, Diablo Immortal is actually a great ARPG to play on your phone.
V4 is an MMORPG with a huge open world and fun gameplay. It is very similar to Black Desert as it also comes from a Korean-based developer.
I had the most fun playing RPGs on mobile with Dawn of Isles. This game is developed by a Japanese company and has very beautiful graphics and the gameplay is very well optimized for mobile as well
Evil Lands is another console-quality RPG. This game really reminded me of Skyrim. The game is really well developed and worth trying. It also has multiplayer and PvP game modes
A3 Still Alive takes place in a dark fantasy world with an emphasis on PvP battles. It has battle royale mode, 100 vs 100 massive battle mode and more.
Mysterious Quest is one of the best looking RPG on mobile. The game has everything you could want in a mobile ARPG and also has great graphics. It will take some practice to get used to the controls and the way things work in the game, but it will be worth it.