LibreOffice snap is the slowest launching snap, Android Studio, VS Code and Firefox post-startup launch time is not noticeable so it’s not “it’s snaps being slow to launch” problem but more likely something else. Notice that the deb version launched instantly. Launching via terminal shows no error messages or hints/warnings.
libreoffice seems to use a few wrappers on startup (to set up java etc) that might have an impact here.
looking at the snapcraft.yaml it already uses lzo compression (which was solving the “all snaps are slow” issue for most snaps).
you should open a bug at: