Slow cold starts on Ubuntu are a known issue with Canonical's Snap application format, as acknowledged in official blog posts like https://ubuntu.com/blog/impro

Slow cold starts on Ubuntu are a known issue with Canonical's Snap application format, as acknowledged in official blog posts like https://ubuntu.com/blog/improving-firefox-snap-performance-part-3 https://ubuntu.com/blog/improving-firefox-snap-performance-p... If you can install a Flatpak or .deb package of Firefox, you should regain that performance. Found a post recommending a "Mozilla Team" PPA at https://ubuntuhandbook.org/index.php/2022/04/install-firefox-deb-ubuntu-22-04/ https://ubuntuhandbook.org/index.php/2022/04/install-firefox..., but I last used Ubuntu 15 years ago, so I can't speak to the specific recommendations therein.