Simplifying wrapper classes

Yes.
implicit classes are only valid in Scala 3 as a deprecated feature, useful for cross-compilation.

then it needs more work.

Feel free to go to the contributors forum to check if someone has already pointed out the same problems that you have or if not, then it may be worth to raise them there.

I personally would find that hard to read and understand.
Although, I also usually use this explicitly except when accessing constructor arguments; so maybe is because I am used to be explicit.

In any case, again, you may propose that in the contributors forum.

Extension method in Scala 3 means we have a method of some class A that is pretending to be a method of class B. More precisely, the method takes an argument a and the call is written as if a method of a is called, but really, a is just an argument, and this still refers to the object that the method really is a member of.