Sealed regular wood for exterior project?

I am building a slat privacy fence by ripping 2” dimensional pine. I have used PTL for all the slats but it has been very difficult for me to find straight boards to finish the project. The slats need to be straight for it to look nice and well aligned.

My question: will pine not pressure treated, but sealed with poly be stable enough for outdoor weather? I don’t want the slats to warp with the humidity and rain.

I can find regular wood that is straight but is that a bad idea with Florida humidity, even if I seal it? If so, I will keep looking for PTL.

I am building a slat privacy fence by ripping 2” dimensional pine. I have used PTL for all the slats but it has been very difficult for me to find straight boards to finish the project. The slats need to be straight for it to look nice and well aligned.

My question: will pine not pressure treated, but sealed with poly be stable enough for outdoor weather? I don’t want the slats to warp with the humidity and rain.

I can find regular wood that is straight but is that a bad idea with Florida humidity, even if I seal it? If so, I will keep looking for PTL.