I used Move To iOS and it took 3 very long attempts (about 2 hours per try) between which I had to reset the iphone because WhatsApp officially only lets you try once. Very importantly, make sure both phones are plugged in and set to keep their screens on/never lock. If either phone locks or turns the screen off, it’ll hang. It’s a bit janky but I was very determined not to lose all my chats, since WhatsApp is the #1 thing I use my phone for. I suggest putting your sim in your old phone, making sure WhatsApp is up and running there, factory resetting your new iphone, and trying to make Move To iOS work for you. As far as I could make out, it’s the only official way.
It’s really baffling to (very deliberately) have no option in the camera app to turn off shutter sounds - as if it’s some kind of moral or legal requirement - but then allow you to turn it off globally via silent mode. It’s the single strangest UX decision on this thing.