#Magento 2 upgrade #schema may not work due to #version #mismatches, broken #upgrade scripts, or #missing module version updates in module.xml file. This often leads to #schema not applying #correctly during the php bin/magento setup:upgrade command.

Using a Magento 2 Upgrade Service helps identify issues like:
Incorrect logic in UpgradeSchema.php
Skipped version checks
Incomplete setup #scripts
# Module conflicts or database #ERRORS

Visit - https://webkul.com/magento-2-upgrade-services/