Question: I have used snap package manager to install several applications on elementary OS. But when I want to start any app it may take a long time (up to several minutes). Sometimes app does not start and I need to click on app icon and wait again.

There is no same problem with default elementary OS AppCenter. These apps open quickly enough.

Answer: 
I've heard of similar issues with Snap apps off and on. One easy alternative is to use Flatpak apps from Flathub when apps exist in both places.

To install an app from Flathub:

1. Visit the app's page on [Flathub](https://flathub.org/apps)
2. Click the **Install** button on the web page
3. Depending on your browser, Sideload may open automatically. If not, choose to open the downloaded file with **Sideload**.
4. Read and agree to the implications of installing an untrusted app from Flatpak.

If this is the first Flatpak app you've installed, it might not show up in the Applications Menu until you log out and back in—future Flatpak apps will show up instantly. You can then uninstall the snap version.

It's typically recommended to use Flatpak apps on elementary OS instead of snap because elementary has [officially backed Flatpak](https://blog.elementary.io/elementary-appcenter-flatpak/), elementary OS supports Flatpak out of the box, and elementary developers have put [significant work into](https://blog.elementary.io/updates-for-october-2019/) making sure it's easy to install and update Flatpak apps without having to use a Terminal.
If your snapd version is older than 2.36.2, it might be a font-caching issue, as written [here](https://www.omgubuntu.co.uk/2019/03/the-cause-of-slow-snap-app-startup-times-has-been-identified).