I have concerns about retinol creams but is it true it should be part of 20yr olds skin care routines?

So I hear it's a good idea to use retinol creams but that you can't wax after you start using them but what about threading or hair removal creams are those okay? I also wonder can I use something else instead like vitamin C moisturizer or does vitamin C moisturizer require no waxing when you start using as well? If you could also tell me why waxing is no good when using those kinds of creams i'd really appreciate it.