Back carrying sos

Any tips on getting a good seat with a woven when back carrying?

Bub is 7.5 months old and sits independently. Has always loved being worn but it just took tall for me to have on my front comfortably (his head is too high under my chin/in my face and my back aches if I have him lower down). And I can't seem to get on with hip carrying, I just find it so uncomfortable, plus he leans constantly.

I've been trying to practice some back carrys with him and he loves the hip scoot (literally will laugh and giggle and shout with glee as I position him on my back). However that's where it ends. As soon as I try to then begin tying my wrap he goes stiff as a board, straightens his legs, popping the seat and sliding down my back. We then go round and round in circles like this until he's cranky and I'm frustrated and sweating with the effort of it all.

I have never managed to get a seat secure enough that I trust he won't just straighten his legs and slide down my back as soon as I take my hand off his bum.

I've looked at half buckles and mei dais out of desperation - but why should I buy yet another carrier when my woven should be suitable for back carrys. I just want to be one of those zen mamas who can yeet her bub on her back and crack on with life but I every time I get my wrap out now I feel like I'm just arguing with my baby 😭🤣 SOS. Do I just accept he'd done with being worn and I'm now a pram person? Or is there a solution I'm missing?