I've observed, that on my installation of PopOS 24.04, when I run commands in Terminal and sometimes when starting other applications like Firefox the time until it starts or I get a print in the Terminal took some seconds.

I'm not exactly sure what's causing this problem. I have a suspicion that it has something to do with Valet for Linux which I use for PHP development. It uses DnsMasq and maybe this is what causes the slow Terminal commands as it changes the way hostnames are resolved on my system.

Nonetheless you can fix this issue by adding your hostname to /etc/hosts.

# before
127.0.0.1   localhost
::1         localhost

# after
127.0.0.1   localhost your-hostname
::1         localhost your-hostname

After this, all should be as fast as it was directly after the installation of the OS.