Quite possibly not. Remember that the admins running lemmy instances have very limited revenue so paying for servers is an issue. Some instances even encourage posting links instead of images to save on cost.
Videos are in a league of their own when it comes to size and therefore the server power needed. Lemmy probably can't afford it. Its the price we pay for freedom and no ads. You have to link videos.
I use ESET and rate of false positives is very low for me (as long as you disable detect "potentially unwanted applications", it asks during installation).