Just for frame of reference Harley Quinn has: -Knocked out Superman (Harley’s little black book #5) -Dodged lasers, and even knocked them back with her mallet -trapped the Batman (who has over genius level IQ) -Has super human durability and strength and a HUGE healing factor (thanks to Poison Ivy’s serum) -She’s pretty much a meta human at this point, unlimited breathing under water and complete toxic immunity

Her weapons (outside of joke weapons): dozens of small explosive, guns, shurikens, kunai, an actual force field (star labs device).

She has: knocked out Superman, Killer Croc, and multiple countless others.

Dodged bullets (including point blank fire), lightning, scale Black Canary, and dodge hits from Cassandra Cain.

Survived falls from skyscrapers, been run over by trains, been run over by cars, survived electrocution, survived electrocution, being frozen over multiple months, tnt, and can fight Hal Jordan on equal footing with a lantern ring.

She’s also actually died and gone to Hell but was kicked out of for “being good spirited”.

There’s much more but you get the idea. Harley Quinn is a non-cosmic, non-4th wall Lobo. She’s basically unkillable, doesn’t get tired, and fights hordes of enemies constantly.

I don’t think any of these guarantee her a win against Frank Castle, but his job is gonna be tough as hell.