The thing that eats the most resources is joining very large, public Matrix rooms. If you don't do this, it won't be resource heavy. I've heard of people runni

The thing that eats the most resources is joining very large, public Matrix rooms. If you don't do this, it won't be resource heavy. I've heard of people running Synapse on a RPi 3 (see https://old.reddit.com/r/selfhosted/comments/g9h6au/matrixriot_storage_and_performance_requirements/fotziui/ https://old.reddit.com/r/selfhosted/comments/g9h6au/matrixri... for instance) for such use cases. If you want to chat in large 1000+ member rooms, it probably won't be enough. However, even for such a use case, you don't need anything that is out of reach of a common person, just a few gigabytes of RAM. In general, it's hard to make it go over 3 GiB. My server hovers around 2 GiB and I'm in many large rooms, including the beast that is Matrix HQ. So I would agree that Synapse is not usable on RPi-level hardware in all use cases, but you can definitely run it on such hardware for some use cases. Dendrite is also maturing really quickly and will be less resource hungry.