If you are trying to cut at grade then a band saw.

If you want to yank it out buy a pull jack and get a post puller. Attack pull jack to post puller and crank. It’ll come out.

If the footer is deep or adhered to concrete sidewalk etc you may have to jack hammer it.

Also you can attach it to a truck hitch with a chain and pull.

I worked in the fence industry for a few years mostly doing repairs. We’ve pulled up 6” steel posts with 300 lbs slugs with a pullback and a post puller before.

Frsx….. please do something. Pokes with stick…. Drops further into abyss

This happened to my AMD puts. Went to bed with my 63p worth .04 and walked out of a meeting at 10:30 to them in the money. Same with 63 p for 12/30. Down 5k to up 5k. Saw a 10k swing between yesterday and today. Nuts.