01Own shop, Amazon EU, one marketplace per country
The same 4,000 SKUs described four ways, each with its own required attributes and title limit. The shop is correct, the marketplaces are approximately correct, and nobody can say which one is wrong until something is suppressed.
02A second country, and the compliance surface doubles
An EPR registration per market, a responsible person per product, a CN code per variant — facts with a legal meaning and a different answer in each country. They belong on the variant, not in a folder of PDFs.
03A campaign month, and three numbers
The shop says one thing, the marketplace another, the ad platform a third. You pick one to defend. Reconciliation is the module that fixes this, and it is planned rather than built — we would rather you knew that now.