Well… it was the pandemic, people were sitting at home with a lot of time and not much else to do, so gaming time it is. HD Edition had a similar peak at that in March 2020:
https://steamdb.info/app/221380/charts/
I doubt that AoE 4 brought that many new players into the franchise. I did a poll on reddit in January 2022 when the game was out for almost three months and the vast majority stated that AoE 4 wasn’t their first Age game:
https://www.reddit.com/r/aoe4/comments/s3k9ph/out_of_curiosity_is_age_of_empires_iv_your_first/
That makes sense as since its original announcement in 2017, people were absolutely hyped for a new AoE game. I guess if you’d do the same poll a year later, the figures would be similar.
Yup. I couldn’t care less for the graphics of a game when its gameplay is appealing to me.