Always nice to get the latest model But don't buy hoping it will fix this issue. I just tried it on a 6-week old iPad, running very latest ios, and the problem is the same.
Searching the web, it seems "possible" it is something PocketMags, or perhaps whoever creates the digital version if not them can help with. Suggestions it's something in the video embed code that can be changed. But some of the comments I found were a couple of years old, so possibly a different issue altogether.
As described above, opening it in YouTube works, but is a faff. I've resorted to simply enlarging the page until the video player almost fits the screen. Fiddly to get right though, and avoid triggering the scroll popup menu at the bottom.
Of course, on a desktop, it works OK, and it can be super large.
I have also watched it on my large screen TV using a Chromecast device. But watching AndyY larger-than-life is a challenge