For me, I’m torn between Mushoku Tensei (very good worldbuilding) and Uncle From Another World (has the better direction)
So many isekais have great starts, but fall off execution in the second season. Maybe they run out of ideas, or just had a good concept, but then lacked creativity to keep the plot interesting… So there are a lot of S1’s
Sword Art Online Season 1
Log Horizon Season 1
Level 99 Villainess
Shangri-La Frontier
Rising Of The Shield Hero Season 1
Overlord