Cat is showing a new, unintentionally hurtful behavior that I don't know how to deal with

Since I think it might be relevant to the question, I'll provide a bit of context first. I'm a first time cat owner - I've had Brioche, a rescue cat for about half a year, and my second cat, Nya, for about 5 months. Brioche is about a year old, while Nya is about half a year old.
The two get along great - the play, cuddle, Brioche cleans Nya.
In general, Brioche has always been a very sweet cat - when she first came from the rescue, she was understandably afraid, but in a matter of days, when she realized I was a safe source of food, pets and playtime, she turned into a total snugglebug. She's an orange cat, but in spite of that, she was never really that stereotypical orange cat - she has her zoomies, sure, but she never really went crazy with it, and was always more inclined towards cuddles. She generally often decided to nap near me while I work (I work as a software dev and do about half my hours in the home office) but was otherwise usually calm.

Recently, however, she's been showing a new behavior. She'll walk up to my office chair and stand up against it. That wouldn't be an issue in itself, but for one, she frequently accidentally claws my arm - I'm certain she doesn't mean to, she's never even come close to intentionally biting or scratching me - and she will also sometimes just go jungle gym mode on the armrest, clinging to it with both arms and flailing around.

I've tried to look into what could cause this, but all the frequent causes seem to not apply here. They have plenty of toys and scratching spots around, and they do use the scratching spots. They don't seem to be a big fan of many toys, but I try to give them playtime a few times a day with a laser pointer, which they seem to love. They always have food available - I do give them small portions of wet food in the morning and evening, but they barely ever finish it and seem to just generally prefer dry food, which is always available (and they have a water fountain they frequent to make up for the lack of moisture in the food).

Brioche also frequently gets cuddles when she asks for them. I may be forgetting other ways of enrichment - if more is important, I'll try to answer questions - but I genuinely don't understand what she wants. She'll meow at me frequently when standing up, too. I've tried standing up in case she wants to lead me somewhere, but she makes no sign of doing so. And she doesn't seem to want attention either, since if I acknowledge her and give her pets, she moves away, then comes back.

I'm sort of at a loss, my arm is covered in scratches and I have to admit it's become kind of annoying, and I also worry about her since I have no clue what she's trying to tell me.
I'm just trying to figure out what's causing this new behavior, and how to at least get her to stop, since she does end up slightly hurting me unintentionally.