I'll stand by Shield Hero in its first arc is a fantastic little work. The sheer bitterness of the protag and the unlikeability of all the nominally "good" characters gives it a real proper underdog feel you don't often see actually work.

Everything after that is hot garbage and worth ignoring, but as a completed piece right there I rather enjoy it.

I'm also a huge fan of "I'm a Spider, so what?" but only the manga version. This is because the Manga basically forgoes everyone but titular character for an extremely long part of the run time. Making it a lot more compelling and interesting story, especially as it feels a lot more like a "video game" as these always try to be. With one person trying to grind against monsters who only exist to kill them and then needing to meta game around your class weaknesses to kill things way above your level for mass EXP boosts.

Other versions of the story hop back and forth from the Spider to the rest of the cast, who are all generic isekai cliches, which drags the pacing down with their far less interesting plots. It makes their eventual appearance in the Manga less impactful, but the story starts to fall off from that point regardless.

While its not been translated far enough to call "best" I just enjoy "Hunting in Another World With My Elf Wife" for the simple premise. Which is "I got isekai'd with my fucking gun." No special powers, just a gun and a magical bag to get ammo with. It even skips all the jerking around with "will they or won't they" by making him get married immediately before he even starts adventuring.