Fork LOS is developed by Sairam who is one of the most prominent devs in land community. It's being actively developed with monthly updates. Most of the development seems to have moved to Telegram groups nowadays.That's impressive battery life but does it cause problems in receiving messages on real time cause that's my biggest priority? 4.9 kernel seems impressive. Fork LOS looks like is not much discussed over here. I checked previous pages couldn't found any. Is developer actively supporting it or he closed it?
Only issue with enabling Battery Optimization for Google Play Services in my experience has been delayed Gmail notifications. If you don't want that you can simply choose not to Optimize it.