There's one option available to small projects and actually you already named it yourself:

> relay bots.

Take for example Nim community. It's not huge by any margin, but we have fairly active forum[0], occasionally active Telegram channel and most of activity is on Discord, IRC and Matrix. I've grouped these three because they're almost seamlessly connected with relay bots into one platform. You can join one of several bridged platforms[1] and talk to everyone on Discord, Gitter, Matrix, etc. with quotes, pings and attachments working as you'd expect them to.

It is certainly an extra burden to moderate and manage all of this, but now you can atleast have an IRC archive[2] that's indexable and searchable [3].

On the other hand, having Discord as your *only* place for discussions is plain stupid (read: foolish). Because I know several people, including myself some years ago, that just 'nope out' from using a project when they see that the only place to get support is a Discord channel.

[0] - https://forum.nim-lang.org/

[1] - https://nim-lang.org/community.html

[2] - https://irclogs.nim-lang.org/30-05-2012.html

[3] - https://duckduckgo.com/?t=ffab&q=site%3Airclogs.nim-lang.org...