@OhBanana I can see bits of my MIL in yours... Down to that I think she really does think she's doing what is best for DH, and that when he started withdrawing a bit, she started talking through me.
She got worse when our baby came; and as she felt her "grip" on DH was loosening, she started behaving in weirder and weirder ways, and getting more and more manipulative. It culminated in them shouting at us in public in November, in front of DS, when he was 11 months old. It really shocked him. SD and I haven't seen them since, DH has seen them once, but nothing since the end of November. MIL continues to send odd messages, sometimes strange manipulative messages about how old and tired they are - ignoring that me and DS exist completely - and sometimes ignoring the situation totally and messaging as if nothing had ever happened, about lambs and gardens and random stuff they've seen on TV. DH doesn't often reply.
Anyway - I'd decide yourself, and then with DP, what you're comfortable with and where your boundaries are. My big regret is that I knew she was pushing mine, just with silly little things; and we kept making excuses because DS is a first grandchild and she probably meant well and I didn't want to be a nightmare DIL or make her feel pushed out... and in the end, it meant that her behaviour just got worse.
If she struggles to let you make your own decisions, I'd probably take a purposefully hard line in this now, so she doesn't overrule you on more serious ones down the line - things that would genuinely be upsetting/dangerous, like when to wean, or when to forward face, or when to cut hair. It'll also be an opportunity for her to show that she can listen to you both, and respect what you say. If she can't - I wouldn't be leaving DD with her at all, and I'd minimise contact to whatever you both feel is appropriate. If she can, you'll be reassured for those bigger decisions down the line.
There's honestly no rush, though. DS didn't go away from me for quite some time. I went back to work quite early on but thankfully he could be with me; and the first time he had to leave me for any real-time was 5 months or so, for a few hours. At six months, I worked an event that meant he was with DH for the morning and the afternoon (I met them at lunchtime to feed him) and that was strange, and then we did similar at 11 months - both times I had days I was fine, and days when I was really tearful! My big worry was how he'd do being left by us both as he didn't start nursery until he was 10 months, but he's done absolutely fine - he loves it there, and lots of his baby friends (who started much younger) do too. Plus all of us find it strangely easier dropping the babies there than with family 😅
Anyway, moral of the story - Don't be pressured. I honestly regret that I let myself be SO much. It makes me so sad to think about. I'll never get that time of his life back and it affected my mental health so much. My memories are all tainted by it. If I can stop that happening to you - at least something "good" came from it x