Using DbContextFactory in a singleton class in Blazor

I'm still trying to wrap my head around how to get a DbContextFactory work with a normal .cs class/singleton.

Here's what I have so far:

program.cs:

var connectionString = builder.Configuration.GetConnectionString("Main");builder.Services.AddDbContextFactory<MyDBContext>(options => options.UseSqlServer(connectionString));builder.Services.AddSingleton<MySingletonService>();

MyDBContext.cs:

public class MyDBContext : DbContext{    public DbSet<Models.Users> Users { get; set; }    public DbSet<Models.Orders> Orders { get; set; }    public MyDBContext(DbContextOptions<MyDBContext> options) : base(options)    {        _options = options;    }}

UsersSingletonService:

public class UsersSingletonService{    internal List<Users?> allUsers;    internal void SetDataUsers(List<Users> value)        => allUsers = value;}

UsersScopedService:

public class UsersScopedService{    private UsersSingletonService _usersSingletonService;    //define the DBContextFactory here?    //private IDbContextFactory<MyDBContext> _dbFactory;    public UsersScopedService(UsersSingletonService usersSingletonService)    {        //somehow get the DBContextFactory here?        //        _usersSingletonService = usersSingletonService;    }     public async ValueTask<List<Users>?> GetUsersDataAsync()     {         if (_usersSingletonService.allUsers is null)         {             //how do we get DB context here?             var myDBContext = _dbFactory.CreateDbContext();             var allUsers = await myDBContext.Users.ToListAsync();             _usersSingletonService.SetDataUsers(allUsers);         }         return _usersSingletonService.allUsers;     }}

The idea is to use a singleton to store a "cached" list of Users which I can retrieve with a service class. I know how to inject DbContext into a .razor page but how would I use it with UsersScopedService here?

An additional issue I'm facing is the connection string is in appsettings.json so I don't know how I'd even pass it to DbContext. This code is based on someone suggesting using a DbContextFactory, but I have no idea how to use it.

Can anyone provide any suggestions?