SUMMARY

I'm on Neon with Plasma 5.23. Every time I start Discover, it takes about three minutes to load the Flatpak list (and it doesn't ever load Snaps, but I'm filling another bug report for that).

STEPS TO REPRODUCE
1. Update to Neon 5.23 (I don't know if this happens with a fresh install or on another distro. It used to work before the update.)
2. Open Discover
3. Click on the accessibility category and wait for several minutes until Flatpak apps appear

OBSERVED RESULT

It takes about three minutes to see Flatpak apps

EXPECTED RESULT

Even if it takes longer on the very first startup, It should keep a cache with Flatpak apps, so the next time the user opens Discover it should have the list ready. Also, I don't know if this is already the case, but the very first time it loads the list it should keep downloading it in the background even if the user closes Discover, that way the next time they open it the list should be ready.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.23
KDE Plasma Version: 5.23.0
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.3
Kernel Version: 5.11.0-37-generic (64-bit)
Graphics Platform: Wayland
Processors: 6 × Intel® Core™ i5-9400F CPU @ 2.90GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Radeon RX 570 Series

ADDITIONAL INFORMATION
System updated from 5.22.5
/home is on a separate hard drive
Flatpak backend is installed properly