VoiceOver problems on iPad Air 4 running iOS 14.4

I recently bought an ipad Air 4 (ios 14.4). Previously I used an ipad Air 3. The Air 4 has considerably more power so I was not expecting to run into serious new Voice Over problems. Problems are mostly with but not limited to safari. When loading pages from a site with a mixture of text, pictures and videos, VO will start to read the text ok but after a few lines will stop and Safari will completely lock up. After waiting about 20 seconds it will unlock but VO will be chopped up and unusable. I then give up and accept this web site is not accessible. On other apps VO will briefly hang up for a few secons. Anyone else experiencing similar issues?