If you have a sony crt, I think you should play your PS2 on that tbh. Chances are that is what actually looks best.
In my opinion, on flatscreen using OSSC, 480i passthrough looks better (lets the TV deinterlace). However, a few TVs apparently don’t accept 480i over HDMI. Linedoubling 480i has too much flicker imo, even with scanlines.
That said, as far as I’ve read and like Bucko stated above also, Framemeister deinterlacing is really top notch (I don’t own one myself).
But if you are not interested in 240p gaming, and you own a crt, then just stick with crt and save your money.