What I've been doing is regularly getting the .json dumps takeout.google.com and merging them. (for around 4 years now)
I plan on eventually processing that data later to track usual statistics, but also for example my interests over the years (by grouping and then searching for common topics like Minecraft, Haskell, Covid, ...).
My idea is to write a purely front-end application that takes a json file and uses a chart to visualize some interesting information by year, such as the most watched channels for the selected year