@msp2023 I know what you mean, it's a bit tricky sometimes to know how to entertain. Some suggestions:
Bouncy chair or swing - mine likes to sit in his for roughly 30 minutes. Bonus is I can do some cleaning or whatever while he's in it. Alternatively you can massage their feet while they sit
Arrange coffee with mum friends - try and walk somewhere if you can so baby can sleep in pram on the way there and back, then have a wake window while you are there, just sit them on your lap and let them look around at the cafe
Swimming - if you can find a local pool warm enough for little little ones
Take photos! Have a little photo session each week so you can look back and see them grow - put them on a nice blanket and have them in a different outfit each week and maybe with toys etc so you've got a record of their cute tiny clothes
Bath time - mine loves a bath so we do it every day
Bubble time - literally lie them down awake and blow bubbles for them to look at
Reading - sit them on your lap facing the book and read to them. Tbh if you want it doesn't really need to be a children's book, at this stage they mostly just like the sound of your voice. You can read something that actually interests you.
Dancing - play music and spin around, bob up and down and generally move about. Bonus for this is it's about the only exercise I really get now!