[MatmaRex]

Well, I don't know how to put it into strings.xml specifically, but there are localisation systems that handle it without much fuss. It requires a bit more effort from developers and translators, but it's not that hard in concept.

For example, Fluent (https://projectfluent.org/, used by Firefox), or MediaWiki's localisation system (https://www.mediawiki.org/wiki/Localisation#Message_paramete...).