I apologize for not answering here sooner: I didn't receive the notifications, so I thought there was no answer! I realize that I was wrong!

From my side, I don't know if what I'm going to say is very rational, but the problem was solved quickly, because in affinity, I just had to open the .svg file and then give it the resolution of 300 dpi, to find my file with the right size. Changing from "not much dpi" to 300 dpi did not affect any features of my image. So for me it's ok!