But you can install apk from outside the store.
I don't think just downloading and installing works now.
After UI 3.0, you will probably get an error saying "service not available in the region" even if it's downloaded and installed using an external apk.
Happened to me. Had to use VPN and install from Galaxy Store. Afterwards it worked.
You can access more customisations via Good Lock.
Latest version: https://www.sammobile.com/apk/good-lock/samsung-good-lock-2-1-00-1/
All plugins are available in the above link.
Extremely useful! You can do a LOT of customizations.
Check out some guides/videos on YouTube to get the hang of it.
Downloading and installing might be tricky, first try installing using the links commented by Dineth (apkmirror) or by Nipoo (sammobile).
If you get an error saying "service not available in the region" in app even after installing, then do this trick:
Remove the SIM. Force Stop Galaxy Store. Clear app storage data and cache. Then connect to a US VPN. Then start Galaxy Store. You will then see the US store, so you can search Good Lock directly from the store and install.
Along with it, download the plugins also.
After everything is done you can disconnect the VPN, insert your SIM again and work as normal.
If the Galaxy Store doesn't load in VPN connected country, you can use apkmirror or sammobile links while you are VPN (and SIM removed) and download everything from there.
You will need VPN anyway just to download and install, afterwards you won't need it.