Maybe also look ip a good component library, for C# I use MudBlazor, which has great documentation that helps a lot to pick the right component for the job, and a lot of the hard work is already done in terms of styles/themes.

For my apps I use the MVVM pattern and write all the backend logic first, then that helps me narrow down the right way to display it.

10GPa is about 2 billion footballers piled on top of a football field.

tldr: he uses offensive programming

Assuming this is C#, you could just make Reservation a record type, which can be defined with a one line primary constructor, is immutable and has value type equality. Second example is an insane amount of boilerplate.