I was there June 2023 for a second visit, five years after our first trip - Flew Delta from Edinburgh > Atlanta > Salt Lake City > Bozeman and back from Bozeman > Minneapolis > Amsterdam > Edinburgh - Delays and flight changes were the order of the day from the time we booked it until we were in transit - but we got there and back.
Stayed in Gardiner at the North Entrance for seven nights split between the start and end of our fortnight there and in the middle of our trip we stayed three nights in the park at Canyon village and then three nights in Cooke City at the North East Entrance.
09-06-2023_Yellowstone_1004 by
David Young, on Flickr
We were happy to get up early and be out of the door at first light looking for wildlife and we saw bears, moose, elk, wolves, coyotes, pronghorn, owls and loads more before breakfast.
If you're more looking for geysers etc then Grand Prismatic is the most extraordinary thing I've ever seen we walked to the overlook in 2018 and it's spectacular. On our 2023 visit we called in at Norris Geyser basin after being up early to photograph a grizzly family - the World's biggest geyser 'Steamboat' was erupting the day before as we drove past and was still;; going impressively the following day - we wandered up and got rained on by it.
We were there for wildlife viewing and photography - best locations for that in my experience are in the North of the park - Cooke City to Tower Junction through Lamar Valley is wonderful in the early morning and evening - and in the East, Hayden Valley and East of Fishing Bridge going out towards the East entrance- The West side of the park is where most of the geyser activity is and gets very crowded during the day.
Here's a link to some of my pics;
https://www.davidyoungphoto.co.uk/gallery/Yellowstone-2023/G00004eImM0DRby4/