I think you're going to love the PM2 Model. Now it's just a matter of deciding on a steel.
As Ferider and others have echoed M390, 20CV, and 204P are all pretty much the same steel from different foundry's.
The Bento Box blue M390 is what I chose for that use years ago, in the hot and humid Florida area. Below is no glamour shot, nor was it intended to be. Just an honest pic of a well abused, and neglected construction user.
I jam this blade in drywall when my drywall saw is in the work van (never torqueing the blade sideways however). I cut data wire with it when my snips aren't with me on the scissor lift. I'll shove it in an access hole to cut insulation from the back, all the while the edge is rubbing up against unsmooth metal. Also, gets called in to cut pallet straps, zip ties, and all sorts of things that I have other tools for, it's just quicker sometimes to use the knife, because it's always with me.
I don't bat an eye at using this $200 knife to abuse the living hell out of, it was purchased for this exact purpose. Plus with so many backups of steel in that same family, there's really no fear if it gives up the ghost one day.
Oh, and the reason mines so dark, crappy phone photo, and left Bar Keepers Friend in a water mixture (as a paste) on the blade for 12 hours. Only intended to leave it on there for five minutes, but friends showed up, with beer, and well, the cleaning job kinda went sideways.
The rust specs are from metal shavings from electrical and energy management panels we drill into frequently. Never had a spec of rust with this steel from sweat (for what that's worth). Hope that helps!
Welcome to the forum.