At around that age, DD used to fight sleep, too. The only thing that worked was either walking her to sleep in the hug a bub. That took aroun 15 minutes, but I had to keep her in there for the remainder of her sleep or she'd wake up again. So I did that for most day sleeps. Or I could feed her to sleep but that took anything from 30 minutes to 2 hours!!! For her to be asleep enough so I could sneak out of bed. So I only did that at night time.
I didn't set myself up for struggles. Things actually got easier and easier and it ended up taking less and less time. There was a period around the 9-12 month mark where things got harder again, but that co-incided with huge developmental milestones and lots of teething, so I don't put it down to co-sleeping and other gentle methods.
We co-slept at night time full time for 6 months, then part time for another 6 months, She still comes into our bed around 5am for a feed and a snuggle and sleeps there til 7 or 8.
She took almost all her day naps in the HAB for 3 months, then partly HAB, partly my bed (sometimes with me) for another 3 months, then her cot for 3 months, and since then, she's been taking all her day naps on my bed because now she can get out safely when she wakes up (usually without me, but I wish I could afford the luxury of having a nap with her).

I hope you find a solution that works for you.
Saša