I saw several vocoded movies on Youtube, and I wanted to vocode the entire Sailor Moon and Puella Magi Madoka Magica series to MEGALOVANIA or BIG SHOT.
First I have to rip them from a Blu-Ray or DVD. Which disk drive to use, and I want to use MakeMKV (makemkv.com).
Second I also need a suitable video editor for the neon effect, and an audio editor such as FL Studio with a vocoder plugin to vocode the audio to a song.
I don't know the first thing about vocoding, but I would focus on step 2 first. It makes more sense to me to first figure out to vocode a minute long clip (the clip could be literally anything), and then figure out how to source longer videos.
I think most vocoded meme makers use Vocodex.
https://www.image-line.com/fl-studio-learning/fl-studio-online-manual/html/plugins/Vocodex.htm