I only want ae 2021. this is because my plugins don't work with ae 2022 as well, and my coloring presents dont show. I have uninstalled 2022 many times. I don't think i need to update ae2021 at this point because it seems that updating it means downloading two versions of the software. Along with that, I downloaded media encoder again because it stopped working for a while and ae2021 always says that it isn't downloaded even when it is. does this mean im downloaded too new of a version to work with ae2021?
You need to have the same year of Media Encoder installed with the version you want to use; even the beta of AE requires the beta of AME.
You can also have two different versions of AE installed simultaneously so long as they are different years, so you can have 2021 and 2022 installed side by side (with their respective Media Encoder versions). Just make sure you uncheck the option to "remove older versions" when you upgrade so that the prior version is not deleted.