I've been using Matrix + bridges to fill that gap. I use IRC, Telegram, Google Chat, Discord and WhatsApp all via bridges, so I only have to interact with a single interface and all my chats are in the same place.
Before that I used first Trillian, then Pidgin. Then seeking persistence across clients I started using bitlbee to access everything through IRC, but that really sucked for media-heavy things like Telegram. My current setup of my own Matrix homeserver + bridges has been working great and feels way more liberating than using 6 different apps.
Which bridging software do you use for some of these? I looked into doing something similar, but all of the ones I saw (at least for Discord) require manually duplicating each Discord channel in Matrix, and it looked to be a bit of a hassle.
this, but I bridged them all to IRC by custom means, which is the easiest to implement and allows people on all platforms to talk in the same channel-equivalent.
the media issue is solved by using a more modern client that can generate embeds (e.g. glowing-bear for weechat-relay).
custom reactions aren't rendered irc-side, mostly because I can't be bothered, but @mentions and all other platform-specific messages are properly translated.
I considered forgoing the channel bridge and writing a custom IRC server that mirrors a discord/matrix group, but I never got around to it.
Before that I used first Trillian, then Pidgin. Then seeking persistence across clients I started using bitlbee to access everything through IRC, but that really sucked for media-heavy things like Telegram. My current setup of my own Matrix homeserver + bridges has been working great and feels way more liberating than using 6 different apps.