No you are not being unreasonable. When you move out of your parents house, you need to use your own address.
My D lives separately and uses her own address for stuff. She really doesn’t get much mail at all. And she says most of the mail that she gets is junk mail, which she throws out. She’s gone paperless for most her important stuff like banking, car insurance, bills, etc. The only important mail she gets are things from family and friends (cards, postcards) and she can let them know when she moves. She also does get stuff from her employer and the DMV (car registration notices), but it’s easy to let her employer know when she moves and you can change your address with the DMV online. Her renting has not been a problem with getting mail.
That said, when she had to order a new phone, she had it sent to our new house because she knew H and I would be home when it was delivered and she didn’t want it sitting on her apartment stoop all day…I think that sort of thing is reasonable. When my niece was engaged, she had the gifts sent to her in-laws house. They were retired, so they’d usually be home during the day. My niece and her fiancee worked full time and there apartment was right at the front of the complex, where it would be easy for someone to swipe a package from their doorstep and run off from it…
I’ve had important things mailed to me at work too. And one of my co-workers had a package stolen off of her front porch, so she’s started having stuff delivered to work as well.