Why does my 480i look sharper and cleaner than my 480p?

Hi y’all. I bought a bitfunx gc adapter. Plugged it in and was blown away. Clean and sharp image. When I went to play in the menu I noticed I was out putting 480i. So naturally I was excited to see 480p. But I could figure out how to do it in the menu. I turned scanline doubler on and boom outputting 480p but the image looked awful.

Please what am I doing wrong?