Are you going to elaborate in the specific nature of your issues or leave some bait like that? Riot.im should be trivially installable on most Linux systems, including the raspberry pi.
If you go to the trouble of working on multi-year open source project it shows a lack of foresight to not include a quick install guide for one of the mostly widely sold hobbyist hardware platforms in the world.
matrix-synapse does have quick install guides but a RPi is probably a bit too low spec to run a matrix server that will federate with matrix.org (though it depends strongly on what rooms you join and how many users you have).