You're partially correct. Ubuntu Touch was discontinued by Canonical (the company behind Ubuntu) in April 2017.
However, Ubuntu Touch was picked up by the UBports project (that by now has their own foundation) and has been continued to this day. Currently they are preparing a Ubuntu Touch release based on Ubuntu 24.04 (moving on from Ubuntu 20.04). See https://www.ubuntu-touch.io/ for more.
Regarding the FLX1(s): FuriLabs worked on a way to support Ubuntu Touch apps (that can be found at https://open-store.io/) natively on FuriOS. It's also possible to boot Ubuntu Touch on their FLX1 hardware.
It says "The FLX1s from Furi Labs runs a fully optimized Linux system called FuriOS", never heard of FuriOS but seems they're not using Ubuntu Touch, at the very most it's a fork of it.
