Homeschooling feels like a nightmare

Alright yall I’m not sure what I’m looking for here - advice, encouragement, anything really.. This is our first year homeschooling. My step daughter is in 3rd grade and she is so incredibly smart. I’ve been in her life for 2 years, so not very long but we knew we wanted to homeschool, so here we are. But lately I dread teaching her every single day. She has been so disrespectful, argues with me constantly, takes hours (and I actually do mean HOURS) to get a simple math paper done. Now she’s always been good at math and she was in public school before and it almost seems like everything we’re learning now is just review from stuff she learned in second grade. So not hard for her she just refuses to do it because she “doesn’t like math”. We took a week off school for Christmas break and are back at it today and she literally had the same page in front of her for 3 hours, this was going on before our week break too though. Now, I’m not forcing her to sit at the table for hours on end until it gets done, I’m letting her take a break to eat lunch if it gets to lunch time or I’ll give her a break to go read or play for a little bit if it seems like she’s overwhelmed but at this point it feels like she’s making up excuses as to why she’s not doing her school work. She keeps saying she’s distracted by everything around her, okay so we make sure the table is cleared off and she has only what she needs in front of her. She can’t focus, so I’ll give her a break to reset in hopes that she comes back ready to learn. But lately it has ended up that she just refuses to do her work, then argues and back talks until she gets sent to her room for dad to deal with when he gets home. I’m at a loss. I don’t know what else to do to get her to do her school work.