It is worth noting i have a 2560x1080p (ultrawide) 75hz monitor. The number one killer of fps, that i found, was antialiasing and anisotropic filtering. During the beginning of the modpack creation, i went through just about every forge/optifine/foamfix/betterfps/phosphor/vanilla option and config that i could find that has an impact on fps. I recently have built a custom modpack (MC v1.12.2), and it is currently in a closed late alpha state. Know its been some time since i last posted here, but i want to share some findings (for anyone googling this stupid common issue).