Cat has gotten super aggressive, at our wits end. Help!!!

We've had our cat (5, F) for around 3 years. She's always had a VERY good temperament. She's extremely affectionate, smart and responsive.

Within the past year or so she's started behaving really badly unless she's played with or showered with love constantly. Trying to get up to places she knows she's not supposed to be, knocking and pushing things nonstop, etc.

We figured this might be because my partner's constantly working in the main area because of covid, so we set up a separate office room. The behaviour is much worse when it's just the two of them, she's much better when it's just me and her.

Since he moved to working in the closed off room, it's gotten a lot worse. She's started to go after his feet and ankles really hard when he's walking around, and she's clearly very angry agitated. Even after he stops walking she'll stand there lashing her tail and try to bite him again unless he pets her, at which point she'll snap back to normal for the time being. She's extremely loving and affectionate to him except when he's walking around. It happens multiple times a day and my partner is very distressed.

We've tried spraying with water, saying NO firmly, nothing seems to work. She's a rescue so I'm afraid these things have actually made it worse since she's associating him walking around with punishment/loud voices.

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So tl;dr cat started behaving very badly during covid to get my homebound-partner's attention. After he moved into an office room she started getting very aggressive towards him. NOT play aggression. Help!