Looking for a Vector graphics software. (Smthn like illustrator)

I am right now facing a major problem. Me and my friend started a dtf printing services. But the main problem is the Editing part. We don't want to waste a single part of the dtf printing sheet. So we want to make a blank size canvas and then arrange all the stuff in one canvas. When we want to change the size in centimeters it's just don't work at all in photopea. [Note: I have a very old windows 7 PC and we both have a good phone]