I had that happened to me using i3, the fix for me was

Remove/replace xdg-desktop-portal-gnome with the -gtk variant

As stated here https://bbs.archlinux.org/viewtopic.php?id=286103

Haha, knew it was related to portals. Apps taking 20-30s to open while the system is not under stress is almost always a portals misconfiguration.

Try to remove 'xdg-desktop-portal-gnome' if you have it and then logout the screen

Thanks! Turns out I had xdg-desktop-portal-hyprland left installed from a previous test (now running on i3)

Thanks!
I have this bug with Firefox and Thunderbird on my laptop, but not the workstation. Already re-installed and was equally puzzled as I didn't saw any load either

I had actually given up trying to solve this...now it's fixed.

I'd hug you if I could. THANKS!

Nope, all fine here.

I’ve been experiencing this issue too! Finally, thank you for this

Wow, I've had this for maybe a year now and was just living with it. Figured it was an audio thing, but Firefox only. Hopefully this fixes it.

Edit: yep, fixed! 😮‍💨

I had this kind of problem recently. It was something around flatpack. I removed everything related to flatpack and it solved the problem.