Aesir really needs to start his own bloodline so we can follow them throughout time, but maybe high elves are too op to breed.
I think it's less about "High Elves being to OP to breed", and more about Japanese MC with their typical mentality of not focusing on family building or even romance, especially in Isekai series.
Considering most of the time, those Isekai'ed people lived a lonely life prior. But even after coming to a new world they don't really bother with creating a family for their own bloodline, and are just happy either interacting with some random people who are nice to them and being over the moon about it, or having some cute pet or adopted child to look after, or some girl(s) fawning over them without any actual romantic inclination from the MC.
Instead they focus on a free-life and journeying around, which technically they could have done in their previous life as well, but because of social obligations (not money) they were apparently forced to do office jobs and live an empty life (since apparently based on fictional Japanese norms, if you are an adult, you have to work and contribute to the society; you can't go around enjoying your life or travelling around).
Majority of the time, the ecchi part in those story are just forced so that MC does get some opposite gender interactions, but if you remove those parts you would notice that there is no emotional interaction at all, nor a plan to build a blood family.
You can actually notice that nearly 80% of the Shounen/Seinen series in general don't focus on family building (or even romance for that matter) even if they are Harem. There isn't even actual physical interaction in majority of them either. Family is treated most of the time as "Post Goal" or "Bonus Content", which doesn't need focus and majority of time becomes a plot of epilogue.
Very few series (like Mushoku Tensei, Ideal Sponger Life, Realist Hero, etc) focus properly on family aspect
(aka., having sex and raising their own children) in either their main or sequel series
(not something like Naruto -> Boruto, were the Manga didn't have any romantic focus and suddenly has a wife and children in the sequel; atleast the Anime adaptation and it's movie fixed that aspect for that series).