For months I have been experiencing performance problems with Firefox. The major problem is an extreme delay when I start Firefox. Sometimes I have the impression that my click was not noticed and I click a second time. Then - after long delay - the system tells me that I should close the 2nd Firefox process.
I have installed all updates (as of 2023-08-19) , nevertheless the problem remains. I have got a friend, who uses Manjaro like me. He does not have that delay problem. Which log files or configuration files should I examine on my PC to find out the problem?
It would appear then that you’ve been bitten by the xdg-desktop-portal-gnome bug.
Your profile does not say what desktop environment you’re using, but you need to remove xdg-desktop-portal-gnome and replace it by one that’s appropriate for your desktop environment.