I recall trying the PS2 emulator first.
But, as it turned out, it ran way too poorly compared to Dolphin.
And that's still the case
it ran too poorly? what cpu did you use
Pcsx2 needed constant speedhacks, and therefore it looked unstable and dropped frames while Dolphin gave a clear image and barely ever lagged ( only when using the Twister combo namely, and thats because I had a toaster for a Laptop back then )
And still with this computer, I can up the quality settings on Dolphin much much further than Pcsx2 can.
when was the first patch released ?
It's called better code optimisation on Dolphin's end.
Ipatix released the first patch... around 2016?
I get that games like ratchet and clank would lag pcsx2 but XXL?

XXL runs in 50 frames per second. It has more impact than 25 or 30 ones.
And besides, even on the real PS2 it dropped frames.
Every PAL ps2 game runs at 50fps
So the emulated version ran even worse.
Most games skip half of their frames.
Never played Kingdom Hearts, Final Fantasy X?
XXL may not have spectacular graphics, but since the devs wanted to make it smooth with 50fps, it kinda pushes the PS2.
However the Gamecube had no trouble at all doing that, being more powerful. On top of it, it improved on the display by switching from interlaced to progressive.