My bad, v tired when I replied. That is an interesting feature the only similar solution I can think of is using something like Fossify Dialer (a fork of the now ad-ridden and proprietary Simple Dialer) and use T9 dialing. That could achieve a similar speed / memorization as a gesture.
You could definitely get good enough at T9 to at least call people without looking at the screen.
Dino on Linux and Conversations for Android are both amazing clients imo, but the rest I've tried are SEVERELY lacking. Especially on iOS.
I personally think the future from a technological perspective is SimpleX Chat. Fixes so many issues that plague other private IMs, however I'm waiting to switch until I see that their venture capital strategy is actually sustainable and won't enshittify it.