Then your next best bet is Matrix.org. Not to the same security standard as Signal, but if you don't have a specific threat against you then it's fine.
Something like this happens basically every time I try to use Matrix though. Messages are not decrypting, or not being delivered, or devices can’t be authenticated for some cryptic reason. The reason I even tried to use Element Desktop is because my nheko is seemingly now incapable of sending direct messages (the recepient just gets infinite “waiting for message”).
https://photos.goldstein.lol/share/OIgowBN4Wmi4zlm8DmDP0s8jH...