Those are the sizes that i've been doing.

UTG: I open pot
Mp/Co: I 3x
Button: 2.5x
If folded and i'm in the SB, I open pot (which is 3x).

But I have some questions.

--> About those sizings above, are they "correct" or should I change depending on the table?
Like if there is a whale on my left on the blinds, and i'm otb or CO, can I pot with premium? Just because he is calling anyway and making spewytards. Or would it be a tell? I mean... I open 2.5x on the button with any hand that I opt to play even AATJds, but sometimes I just question myself if would be more EV to raise bigger.

--> If the Button and the CO are the most profitable positions why open 2.5x? Does it make a difference from 3x? If so, why not pot?
Or opening 2.5 or 2.25 kinda makes people "want" to 3bet lighter and you play a bigger pot in position and if I raise pot they would fold or call?

--> Dumb question... if someone limps, the raise to isolate is always pot right?

-->About 3betting. Does it always have to be pot?
I pot oop (like 3bet steal), but in position sometimes I just don't, but than I make the same question... If we are making more money in position, why not 3bet pot?

bump

pre-flop sizings seem fine. can change the sizings to larger ones if ppl are defending wide no matter what and just open a tighter range. as far as 3betting, u can 3bet a smaller size IP than OOP because u might want the SPR to be larger (allowing more room to do stuff IP)

if someone limps u can just add a bb to your normal raise size from that position so that ppl can squeeze to as high of an amount

Pre-flop sizing tells are pretty much irrelevant in worrying about especially at small/mid stakes PLO since the game is already quite complicated that people just aren't going to spend their energy focusing on the fact you suddenly pot BTN instead of 2.5x. And if you spend your time/energy on it then you could be missing out on value from other situations that warrant more time spent on.

That being said, it's possible to have different raise sizings from the same position and still remain balanced if you so wish. But just focus on exploiting the weak players - if they will call pot raises PF then just pot all your premium hands OTB. We don't have to tighten up tho, we can still 2-2.5x everything else we want to play and even limp the weakest hands that aren't complete trash.

I factor my sizing based upon both position and hand dealt...

There really is too much going on and too many different ways to play the game to set solid rules. If someone is telling you , should do this do that, they are usually muppets.

But muppets are also always potting everywhere with any playable hand they see.

sizing is about position and hand strength you want to mix it up a little but not a ton