I noticed that the filter in the directory for Date for games stopped at the year 2019. It would be nice if the year 2020, 2021, and 2022 were added, with the ability to add more years as they come up.

That's weird, I notice the feature is either removed or highly erratic. I don't know how I did it, but I managed to get an instance of year filtering as shown in the big image.

but recently I only see  a shorter list which is weird.

Try following this link for year filtering? Top free Adventure games from 2015 - itch.io
if you end your itch io URL with year-#### where # is replaced with the year I think that gets you what you want.