Out of memory while deploying (I decreased the file sizes as much as possible!) raster maps in Shiny

So I again and again have out-of-memory issues while my deployed app is opened.
In the past, I had the same issue with my small app with leaflet outputs and raster files. So I figured out to decrease the number and spatial resolution of my raster layers.
Making it to 4 layers with 1 Mb size each (60 m spatial resolution of each). Now this works.

But when I created a new dashboard with 2 panels, one with the same 4 raster layers (1 Mb size each), and the second one with 2 raster layers (300 Kb each, 60 m resolution as well), it produces only
out of memory
out of memory
out of memory!

I even commented everything related to the new second panel. And it does not work again! I am tired.

I stored everything on my Github. I cannot believe that something makes an image of app larger than 1 Gb.