Hello,
The following should work:
$PublisherAppClientId = 'xxxx-129c-4435-89f1-bedb3175afd6'
$PublisherAppClientSecretSecret = 'FpD8Q~Sxxxx'
$appId = 'tenantID'
$scopes = 'api.businesscentral.dynamics.com/.default'
$token = Get-MsalToken `
-ClientId $PublisherAppClientId `
-Scopes $scopes `
-TenantId $appId `
-ClientSecret (ConvertTo-SecureString -String $PublisherAppClientSecretSecret -AsPlainText -Force) | Select-Object -Property AccessToken
$token.AccessToken | Get-JWTDetails
$authContext = New-BcAuthContext -refreshToken $token -tenantID $appId -includeDeviceLogin
$apps = 'C:\Users\xxxx\Documents\AL\ALProject3\Default publisher_ALProject3_1.0.0.0.app'
$environment = 'SandboxBE'
Publish-PerTenantExtensionApps -bcAuthContext $authContext -environment $environment -appFiles $apps
Default publisher_ALProject3_1.0.0.0.app
Publishing and Installing.......completed
Is that something you can try as a workaround? You can also raise a question on Freddy's Blog.
Hope this helps.