Milestones

My baby can sit unassisted but can't get herself into the sitting position by herself if that's what you mean. My baby does a crab shuffling to move herself around on the floor and has for months but isn't on all 4s to crawl or anything. If she's sitting in front of me and wants up she can use my shirt to pull herself up but doesn't do this with furniture

My boy is the same, he's not interested on sitting although he can. He's not crawling yet either. He's got a lot of strength in his legs so I'm not overly worried atm.

She has just yesterday been able to sit by herself for a decent bit of time but has to be placed in that position. She is desperate to stand all the time but will only do it pulling up from our hands. She moves around on the mat but its either backwards (still not sure how she does this) or by like squirming forward to grab stuff.

Same here, just pivoting a lot, no crawling, no sitting 🤣
Every baby is different! One day no one will be able to say who did all these things first. I'm not overthinking it at all.
From what I see baby girls are more advanced than baby boys 🤭