You could safely increase your “Memory Limit” up to 5500 MiB. And if you told me how much free space you have on your SSD, preferably while you have a project open in Krita with a large image, I could tell you how much you can increase the lowest bar “Swap File Size” without colliding with the system.
It would be optimal if you had a second SSD in your computer, then you could move the swap file of Krita there - that’s how I do it, for example, and can save myself the following security precaution.
I’ll write down the rule of thumb for this, which is related to the swap space you need: With your 8 GB of RAM, Windows should be allowed 25 GB of swap space. Why?
This is based on experience. Up to 32 GB RAM, the existing RAM will be multiplied by 2 and rounded up to the nearest 0 GB, add 5 GB reserve for Windows, and Windows will be fine with that. (With 32 GB RAM, 75 GB would have to be reserved for Windows! (2x32=64 >> round up to the next 0=70 >> + 5=75)) With more than 32 GB RAM it is sufficient to leave at least 80 GB free space on the disk for Windows, who has more and can, can reserve more.
So in your case 2x8 GB=16 GB, rounded up 20 GB+ 5 GB security=25 GB which should be left for Windows. Then subtract this from the free space of the SSD to determine the maximum possible “swap file size”, Krita allows up to 64 GB swap files.
Assuming you have 70 GB free on the SSD when Krita is running, this minus the reserve for Windows 25 GB gives 45 GB maximum “swap file size” that can be safely allocated to Krita. You can specify more, but if Krita and Windows then “fight over the memory”, it can lead to a crash and data loss.
If you had 89 GB of free space on the SSD while running Krita with a large image on the canvas, you could now allow Krita a full 64 GB of “swap file size” without risking a collision with Windows (89-25=64).
This way you might be able to get a little more performance out of Krita.