If you want to work full time, then you almost certainly need full time help. If you can flex your hours, you might be able to hire 4-5 hours of help during the day, and make up the rest at night after your partner gets home to watch the baby. But honestly, unless your baby is an unusually good sleeper, you are going to be exhausted, and it's going to suck to have to work into the evenings.
I'm sure there are some exceptions to this - magic baby or job that doesn't actually require sustained concentration. But the vast majority of mothers I know could not have succeeded at a demanding job while watching their baby. For this reason, as other posters have noted, your employer probably expects you to have childcare while your work.
Frankly, I would not count on even being able to work in the same room as your baby. Neither of my kids wanted to play with anyone else if I was in the room. I worked from home 3 days/week for years, and my kids were watched in my house by my father for the first 6 months after each maternity leave. It only worked because I locked myself in my home office while my dad played with the baby downstairs. He would text me to come downstairs to nurse, but otherwise, it was like I wasn't there. Your kid may be different, but my experience was quite common among my friends. Plus, where I am, it's actually much harder to find a nanny if you tell them you are working from home. Good nannies are professionals, and don't want to be micromanaged all day at their jobs. And again, for most kids, it's easier to keep the kids happy if mom/dad isn't right there.
I would focus your efforts on finding an excellent nanny whom you can trust absolutely. Get recommendations from trusted friends, offer market-beating pay and benefits (which it sound like you can afford), and then let the nanny do her (or his) job.
