It's literally ironic when you use "literally" to mean "figuratively."
Which misused words do you correct most often?
Actually myriad in Greek means a UNIT of 10,000 – it’s a noun, not a numeral, and it’s used with the article. So you can say in English “a myriad of X” meaning a ten-thousand-strong unit of X. Just like we say a trio of X (a unit of three). According to Merriam-Webster the noun usage (as borrowed from Greek) is older in English, but at some point it started being used as a numeral adjective as well (myriad misuses), but today both uses are good English.