Is it possible to submit the same extension but for different magento versions? For example one that is compatible with magento 2.2 and other only compatible with magento 2.3 ?
Yes, You can use in both version. There would be minor patch changes.
If any issue occur then Check the version in composer.json and coding stranded for that specific version. You can check the extension versions update change log on extension store .
@5e42aa0edd4e9 yeah you can do that, instead just release a update version with compatibility with upgraded magento version and some other features which you want to add.
Instead of adding new, an updated version of previous one would be more beneficial.
Hope it helps!