PAA: When the Rama says L’histaper, he means a haircut. Everyone had beards back then anyway. So there’s not such a lack of Kavod Shabbos if a beard is a bit unkempt after a month without trimming it.
However, nowadays when people are clean-shaven, there is certainly a P’gam in Kavod Shabbos if one has a scraggly quasi-beard that just looks awful. Those Poskim who allow shaving every Friday during Sefira don’t think they’re arguing on the Rama. They say the Rama is talking about a different Metzius. Ain Hachi Nami, they hold that people with beards cannot trim them on Fridays L’kavod Shabbos.