And if PiGallery2 isn't your cup of tea, here are some other contenders:
https://bpatrik.github.io/pigallery2/ hits the spot! Run by itself or via Docker, point to a directory with your photos (nested dirs supported) and voila!
It has even a neat #openstreetmap visualisation of places where you took the photos. I love it!
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.