Boy am I confuse with baby clothes sizing.

I have 8 pieces of newborn onesies, size 50 in EU. 3 came in a pack, and 5 in another. The 5 pack is SHORT with no stretch at all, and I’d be shocked if she fits in it at birth, it seems like preemie sizing? They are much wider than the 3 pack though.

The 3 pack is about 4cm longer and much more narrow, but seem way too long for newborn.

I also have a 5 pack of 62 (3m) that are the exact same length as the 3 pack at 50, but are way wider.

I don’t know how any of this goes. I know I have to wait to see how big she is etc, but I can’t imagine sending out my partner to have to go buy onesies in an emergency.. I suppose he will have to bring the too small one and make sure they can confirm it’s only the nearest next size up. The only store I know here usually has these things in plastic packages. We don’t have same day or next day or even next week delivery where I am. It takes forever. And I do not want to have 20 pieces of newborn things in case she outgrows them quickly.

What would you do? How do people do this. Help. I just want to make sure that first week or two of trenches isn’t stressful with having no clothes that fit at all