Others have noted altertnatives like mattermost, etc....But if still interested in matrix, you can always pay for providers to host it for you (and of course manage everything related to infrastructure, etc.)...plus, some charge a tiny bit more per each bridge to connect your account to discord, Telegrma, etc. In essence, you have a single account - through a paid matrix provider - but can interact with your friends on other networks. See:
https://matrix.org/hosting/