But Im terrible at playing or writing any type of metal. Not 80s metal but things like Scale the Summit, Haunted Shores, Bulb, ect... It just never sounds anything like what im hearing...perhaps its my gear? I use a Gibson with P-90s and a Podx3. The Pod has pretty good tone control but I cant help but feel like single coils are not helping. However, if I put on a blues backtrack I have no problems and can get into a good groove with ease and my guitar sounds great on clean. But if I try to write anything metal it just sounds really cheesy and I go back to blues jammin.

Id really like to write this kind of material but whenever I try to even learn accurate tabs I just cant get them down because I just cant get that "sound". Would new gear maybe help this? I know new gear wont make me better but Im thinking p-90s arent able to do the job.
Just another Sheep in the design of the Almighty Machine.

Gibson 60s Les Paul Tribute (Sunburst)
1999 Ibanez RG470 (TitaniumIce-MIJ)
Jackson RR3 (Trans-Red)
Peavey 6505+
there's p-90s in a lot of recent builds of metal guitarists that i remember. typically they're pretty souped up, but you can get metal sounds with a whole heck of a lot with a little fiddling.

have you tried transcribing their music, or, better yet, since all of those projects are heavily production/tone-based, emulating their tones or mixes (p-90s or not)?

you don't have to get anything on the dollar, but just working at it and trying to take in how they did it in contexts that you wish to use as an influence is absolutely the best way to approach writing within a certain genre or style
modes are a social construct
your gear has nothing to do with it. P90s arent for high gain amplification. high output humbuckers are the only solution for high gain. but that only affects your tone, not how your music sounds.

if you can play pentatonic scale well, start learning the minor scale, it only adds a few notes into the basic pentatonic boxes/structure! then move on to harmonic minor --- very typically used in metal

youll also have to learn the major scale, and its a bit difficult to make it sound good at first

in "Scale the summitt" the guitarists seem to know and use chord theory and modal theory very well and it takes years upon years to learn to write this music