Best advice to sell products on Amazon without EAN etc.

Hi everyone,

I have some sports products from a fighting sport from a specific brand.

However, this company has zero EAN or all of those other codes so everytime I try to sell it on amazon, Amazon does not find it and I can’t sell it.

Other brands Amazon dóes find, but then it says I need permission and have to upload some stuff I do not have.

Coming back to this specific brand who has zero EAN or other codes, what is the best way to still sell them legally on Amazon?

Are the codes not that expensive and can/should I apply for themselve? I heard something about GS1 codes from before a specific year that allows you to only pay it once and then you are done with paying.

Hoever, will Amazon accept these codes also?

Many questions and I just can’t seem to find a clear answer. Hope anyone can help me.