Blazor.FileSystemAccess VS Radzen Blazor Components

I would say the short answer is no. On desktop Chromium, you can use the File System Access API, and that's easy enough to use from Blazor, but on Firefox, Safari, and mobile Chromium, that API won't give you the real file system but rather a sandboxed one.

GitHub: https://github.com/KristofferStrube/Blazor.FileSystemAccess Demo: https://kristofferstrube.github.io/Blazor.FileSystemAccess/MemeGenerator

Repo: https://github.com/KristofferStrube/Blazor.FileSystemAccess

To client project, without any changes, just added Appointment.cs, EventConsole.razor, AppointmentPage.razor, AddAppointmentPage.razor, and EditAppointmentPage.razor (copied from the demo radzen-blazor project) and the scheduler component works as expected.

Since you already have extensive C# experience, Blazor will be incredibly easy to pick up. I came to Blazor from WPF and Xamarin, and it just clicked. Microsoft has done an excellent job documenting it, and there are plenty of amazing libraries to use, both in terms of utility and components. Since you're developing internal tools, where design is not a concern, you can get incredibly far, incredibly fast, with something like Radzen.

I'm curious as well. I'm look at Radzen at the moment, but have only installed it on my laptop, have don't nothing else.

Radzen is open source, (here is the datagrid, cause I was trying to see how they were doing the select all)

The second step to take is to go to https://www.radzen.com/

The license at this location would indicate that they are Open Source: https://github.com/radzenhq/radzen-blazor/blob/master/LICENSE