I exclusively shopped in guy mode for decades starting in my mid teens. The first few times was weird but if you don't act "Guilty" no one thinks anything of it, or says anything at least which is fine by me. I even started venturing into exclusively women's shops.
One very nice factor about department stores is that there is both men's and women's dressing rooms. First you grab a pair of men's pants, size Gigantor, then browse for your fem stuff. When ready cover up the women's clothes with the pants, and head for the dressing room. NOT LOOKING GUILTY! lol. No more having to return stuff. Yes, even works for dresses.