How has ownCloud development compared to NextCloud since the split?

Since a couple years ago they abandoned the php version (=nextcloud) and they are in the process of a complete rewrite in go, which that means is faster and uses less resources but all existing plugins need to be rewritten too, and given the small user base nobody is going to do that.

PHP will outlive us all.

And Java will still be active long after the heat-death of the universe

If python is still around why not?