Yep, Tuwunel or Continuwuity seem to be the only reasonable alternatives to Synapse right now. Both are forks of Conduwuit. Tuwunel is the one that was marked by Conduwuit’s author as THE continuation of Conduwuit, and it has some corporate backing. But apparently Tuwunel’s maintainer is a jerk, and after your standard open-source drama community gathered around Continuwuity instead, and it’s the latter that seems to be recommended everywhere whenever someone asks for a Synapse alternative. Anyway, either of them would be better choice than dendrite at this point.