i've seen many posts about not being able to manually install UWP apps, some are common issues like not having VCLibs, UI.xaml, etc. To manually install UWP apps on Atlas, follow these steps.
Apps on Microsoft Store
1.copy the app's micorosoft store URL.
2.Paste the link on this website: https://store.rg-adguard.net/
3.if there are dependencied apperaring, download it together with your app.
in this case the following thing should be downloaded.
Microsoft.VCLibs.140.00.UWPDesktop_14.0.30704.0_x648wekyb3d8bbwe.appx Microsoft.UI.Xaml.2.6_2.62112.3002.0_x648wekyb3d8bbwe.appx MicrosoftCorporationII.WindowsSubsystemForAndroid_2210.40000.7.0neutral~_8wekyb3d8bbwe.BlockMap
4. after downloading all apps, put it all under a same folder.
in this case, i am putting it all under C:\WSA
5.Open powershell with admininstrator access, and mount the folder you put the files in.
in this case, i am doing cd C:\WSA
6.Perform this command for all packages: " Add-AppxPackage YOUR-APPXPACKAGE-NAME"
in this case, i will be doing this command three times.
add-appxpackage Microsoft.VCLibs.140.00.UWPDesktop_14.0.30704.0_x648wekyb3d8bbwe.appx
add-appxpackage Microsoft.UI.Xaml.2.6_2.62112.3002.0_x648wekyb3d8bbwe.appx
add-appxpackage MicrosoftCorporationII.WindowsSubsystemForAndroid_2210.40000.7.0neutral~_8wekyb3d8bbwe.BlockMap
Your Microsoft Store UWP app should be installed successfully.
Non microsoft store UWP apps
1.Perform the Add-AppxPackage Command with administrator access on powershell (steps are on top)
2.If not installed correctly, Powershell will give you a feedback. (normally a missing VCLibs or sth, find it on the internet and install it with Add-AppxPackage)