Yup, fussy periods especially in the evening are normal, if hard! Right when its dinner time usually
And grunting and straining is normal too, my Alice does a lot of it, Oliver not as much but still some.
As far as what to do with a newborn once they start waking up a bit more, you don't have to do stuff all the time, but yeah they love to lay and look at stuff like fans, sun on the wall, etc. and you can carry them in arms or in a carrier around with you while you do stuff and narrate what you are doing when you think of it, the talking is good for their development and gives you something to do. I also read books to them, more for me than them, but still it is something. Or show them family pictures, that's kind of fun for everyone.
My babies are luckily pretty easy going, but there are still times when both are crying and it is tough to not be able to easily pick them both up quickly. I can get them both on my lap on a pillow or my twin nursing pillow, but it takes some doing at isn't as nice as just holding them.