Unrealistic NRR (noise reduction rating)?

Are these NRR rating on for:

• Decibel Defense
  • https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.amazon.com/Professional-Safety-Muffs-Decibel-Defense/dp/B0875TLD6T&ved=2ahUKEwiWxL2ji9OLAxW_fTABHV7QNMkQFnoECDIQAQ&usg=AOvVaw1cwMAQlOy6Cb862zOpDvV-

True or are they fudging the numbers some how?

I have spent serval hours trying to see if the ANSI S3.19 & CE EN 352-1 NRR claimed certificates on https://misophoniainstitute.org/ear-muffs/ are true. On https://misophoniainstitute.org/ear-muffs/ they also have serval other earmuffs with NRR of 31 and above reac hing 37 NRR. On https://noisyworld.org they have stated 31 is very hard to achieve and anything past 31 isn't on the market for earmuffs.

I live in a very loud place and have a hard time concentrating when noise goes on around me, I am trying to find the best way to combat sound. So far I have found earmuffs plus reusable earplugs probably be the best passive noise cancelling and money.

I welcome recommendations on products and methods to block sound.

Most of education on the topic has been from articles from CDC and https://noisyworld.org/