Disgaea games are incredibly laggy

[LunaMoo]

Each game is different and comparing them especially when they are soo different is pointless. It's also completely normal for both 60fps and 2D games(due to hardware being optimized for 3D graphics) to be harder to emulate so combining the two ~ 2D games running at 60fps are easily more demanding than some basic 3D ones running at 30 fps.

The only thing which likely could help a bit is Vulkan api that is if your device supports it and only after it actually starts working on android since it proved to be problematic.
But even then you might still need frameskip/drop enhancing features down/off, live with it and accept the reality of playing on a device that fits your hand aka lacks power. If you can't deal with that, just don't play at all, nobody forces you to ~ dood.