Using MSAL web app authentication together with Redis as token cache, can TTL be configured for the Redis keys?

Question

In a ASP.NET Core 3.1 project, when settings up authentication using MSAL:

services
    .AddMicrosoftIdentityWebAppAuthentication(configuration, "AzureAdB2C")
    .EnableTokenAcquisitionToCallDownstreamApi(scopes)
    .AddDistributedTokenCaches();

Together with Redis as distributed cache:

services.AddStackExchangeRedisCache(options =>
{
        var connectionUrl = Configuration.GetValue<string>("Redis:ConnectionUrl");
        options.Configuration = connectionUrl;
});

The access and refresh tokens are correctly written and retrieved to/from Redis. But when checking the TTL of the key with the Redis TLL command it returns -1.

I noticed that the session data in Redis does get the TTL set based on the configured session idle timeout:

services.AddSession(options =>
{
    options.IdleTimeout = TimeSpan.FromHours(int.Parse(sessionSection["IdleTimeout"]));
});

These findings leave me with 3 questions:

1. Wouldn't it be better to configure a TTL for these keys? Storing these tokens forever seems redundant as they will expire anyway at some point.
2. Is there any way to configuring or add TLL to these keys which are managed by the MSAL library?
3. Is using the LRU cache functionality of Redis a viable/better solution for this?