Microsoft Identity - how to check access token validity and prevent MsalUiRequiredException

I have a Blazor Server app that calls downstream api (Sharepoint Online API) on behalf of logged in user.

However, users are sometimes getting MsalUiRequiredException. I understand that's because the token became invalid.

services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)                   
   .AddMicrosoftIdentityWebApp(configuration.GetSection("AzureAd"))
   .EnableTokenAcquisitionToCallDownstreamApi(sharepointScopes)
   .AddDistributedTokenCaches();

ClientContext SharepointClientFactory()
{
   var clientContext = new ClientContext(siteUrl);

   clientContext.ExecutingWebRequest += (sender, e) =>
   {
       try
       {
           string accessToken = _tokenAcquisition
                           .GetAccessTokenForUserAsync(scopes: effectiveScopes, authenticationScheme: OpenIdConnectDefaults.AuthenticationScheme)
                           .GetAwaiter()
                           .GetResult();

           e.WebRequestExecutor.RequestHeaders.Add("Authorization", $"Bearer {accessToken}");
       }
       catch (MicrosoftIdentityWebChallengeUserException ex)
       {
           //_consentHandler.HandleException(ex); I want prevent this from happening in advance
       }
   };
}

Simple page refresh does not help here, because the authentication cookie is still valid.

1. How do I check the access token validity before the app is shown to the user? (e.g. when user visits _host.cshtml which hosts the blazor app)?

2. Is there any other way to prevent access token expiration during user session?

you can use this to check access token validity

public async Task<bool> IsAccessTokenValid()
{
    try
    {
        string accessToken = await _tokenAcquisition.GetAccessTokenForUserAsync(scopes: effectiveScopes, authenticationScheme: OpenIdConnectDefaults.AuthenticationScheme);
        return true;
    }
    catch (MicrosoftIdentityWebChallengeUserException ex)
    {
        // Access token is invalid
        return false;
    }
}