Sorry to hear you're struggling. My DD is 7 months and I went through a hell of a time with her from about 6 weeks of age due to silent reflux. Within a week of starting losec I had a different baby. We still have challenges but nothing like the screaming-miserable-nonsleeping baby that I had. It was truly an awful time.
Early morning grunting/groaning is pretty normal and common in this age group from what I've heard. I think from about 4-6 weeks old babies 'wake up' a bit from their sleepy newborn state and can be very unsettled for a time and find it harder to sleep. It's a pretty bewildering world. Google 'fourth trimester' and have a read about that concept.
A lot of people swear by the wonder weeks app/book, I've never noticed a correlation between 'leaps' with my DD but the developmental info is interesting nonetheless.
A while back I came across these resources and wish I'd had them in the early weeks, take them or leave them though 😀
We use white noise for all sleeps, all sleeps in cot in dark room day and night (she will have short naps in car/Pram if out though) and up until a month ago we used this fail safe wrapping technique
Our cot is now on wheels (large rubber ones purchased from bunnings) so you can replicate that Pram pushing motion which is our go-to settling/resettling method. Consider putting bub in a wrap carrier during the day to keep her close and upright this saved me for weeks when my DD was very difficult.
That's all I can think of for now. Go you being such a hands on involved dad and getting on bubhub awesome work 👏😀 hope things get easier for you soon.