I think it pretty much depends on what do you want to get across. Going in to 3rd person is pretty great when you want to narrate the story, but focusing in 1st is(IMO) recommended when you want to develop a character for you will not only show of their thoughts and actions firsthand but will...
There you have it then, also, forgot to say but love the concept of evading the isekai and not just because of luck/coincidences but because the MC has the capabilities to evade them, almost all of the isekais i've seen have "average" protagonists, so seeing one with a capable protagonist is...