Automatic accumulated sum when changing month

Hi all,
Semi-noob at Excel here, hoping someone can help I have a monthly sales report that I would looove to make a bit more automatic than it currently is. At the moment, I have to update 2 columns manually each month because it has to sum X amount of cells for the accumulated sales up to and including the month I'm reporting on. Is there any way to make it automatically sum up to and including the month I type in the top? It was fairly easy to do for the 1 month I'm reporting on because it just looks for the month and returns the amount for that one month, but I can't figure out how to make it calculate the accumulated YTD amount when I type in a new month
I hope the attachment works to show I've taken a small snip of the report and put in some random figures for 2022 just to see if I could get it to work Thank you all in advance!

P.S. I should mention that I'm looking to avoid any extra columns or matrixes if at all possible. The "real" workfile is already massive enough as it is (400 rows and A to CO in columns at the moment, plus 3 additional sheets that it pulls data from and these sheets each have around 8000 rows each!)