I built https://stratum.work to get this block template stuff in front of more eyes. It shows real time template data sent to miners to work on and you can watch for similarities between pools yourself.

This thread does a great job explaining the data:

nostr:note1qckcs4y67eyaawad96j7mxevucgygsfwxg42cvlrs22mxptrg05qtv0jz3