Just did a hive inspection because i noticed a dramatic decrease in bee population and activity
Found these grey cells and think its beetles
Any thoughts?
They look like wet caps over normal honey to me. Nothing to worry about.
However, you do have a ton of queen cells in there. I suspect your hive has swarmed. Here are a couple of very good (but long) articles to help you work out what to do:
http://www.wbka.com/wp-content/uploads/2015/04/wbka-booklet-english-PDF.pdf
http://www.wbka.com/wp-content/uploads/2020/03/webAn-Apiary-Guide-to-Swarm-Control-2nd-edition.pdf
In the 1st and 3rd photo on the grey/green part of the comb is mold growing. Your down in bee numbers and with the number of queen cells, and as Dawn says, the colony has swarmed and you have lost about 1/2 of the bees in the hive. SHB fully grown is smaller than a match head so there is no way of seeing them in your pics, but if your hive has them then you should add a couple of traps to the hive.
Cheers
Plenty of baby queens you have coming along there 