You can also go to voice effects, make the voice effect “deep”, turn the effect itself all the way down and the timbre all the way up, and it should sound muffled and low quality.
2000's: Wow, this vid is so good quality! 2010's: Bro, this vid sucks, I can't see anything 2020's: BRUH, THIS IS LIT! We gotta learn how to make those!
i have another trick that works but it takes up more space, make the video that is gonna be low quality, then make an audio of your choice, it just has to be recorded then make the video low quality, extract the audio, then use the vinal to make the audio low quality aswell