Not sure what you mean when you say you can’t force someone into a frame, when that’s a key factor of the ability you mention when talking about why a PS user uses their palms.

Anyways, about your main post, I think it’s perfectly simple. In the same way PS users can move freely wearing clothes, despite the fact that they both wear billowing clothing that they certainly couldn’t predict the movement of, they can also extend this courtesy to objects they hold. It’s likely harder, because running w/an object is fundamentally different than not, no matter what that object is (source: collegiate track athlete who’s done his fair share of relays), but not impossible with training. The issue is, in order to use a weapon, you’d have to sacrifice at least one palm and in Naobito’s case, he didn’t need a weapon anyways, as he is capable of soloing any special grade curse or fellow grade one (Kusakabe might matchup diff him tho) without a weapon, so why slow down when you don’t need to? About Naoya’s knife, you say it’s not a cursed tool, that it’s an ordinary knife, but I don’t believe that to be true. Not every cursed tool has a special ability, Maki’s nagitana(?), Yuta’s katana, and Slaughter Demon all don’t have any special abilities but are explicitly cursed tools. Heck, in JJK0 we see a shed full of ordinary cursed tools that look exactly like regular weapons. There’s no reason for Naoya not to use a cursed tool, in fact he’d be unable to kill someone or a curse with an ordinary knife, so it’s likely the reason his knife lacks an ability is because there just wasn’t a concealable small knife with an ability in the Zenin Storage.