SAO isn't an isekai at all, best isekai in the world is RE: ZERO, unique story with many unpredictable twistsand turns. Good set of characters with a MC which is just an ordinary boii. Nice soundtracks, awesome visuals, great character developments of not only the MC but the side characters too,

From that list I’d definitely go with Tensei Slime. Mushoku Tensei is also a great Isekai though.

Shield hero imo

From the poll my ratings are

Tensei shittara 6/10

Shield hero 8/10

SAO 8/10

NGNL 7/10

Shiled hero or slime

Out of these ngne

>ngne

Nice anime you have there

SAO is not a pure isekai but rather a semi isekai

Just call sao trash