https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikibaseLexeme/+/843986 is another WIP patch that tries to address one part of the migration (replacing filter syntax, e.g. {{'wikibase-add'|message}}, with something else); it fails in CI, though, partly due to the mentioned issues with php-vuejs-templating.

The three subtasks should be all that is needed in addition to finishing Lucas' patch 773276: WIP: Fully migrate to Vue 3.

The main risk comes unsurprisingly from php-vuejs-templating and us deciding how we want to deal with replacing filters such as gloss.language|directionality or 'wikibaselexeme-sense-gloss-redundant-language'|message which is the topic of T321595.

1. If we go with the minimal invasive solution for php-vuejs-components, for which already patches exist, then the overall effort and risk should be limited. I would estimate between half a day and half a week of additional effort for the entire remaining migration.
2. Unclear how long it will take otherwise, that depends highly on the chosen alternative approach.

The subtasks sound good to me. (Though I’m not totally on board with the changes for the “minimally invasive solution” so far.) Does that mean we can take this task out of peer review? (Tech verification, or close right away?)

Let's move it to tech verification. I think it is worthwhile spending some time on agreeing on what way we want to go, as this also might have significant consequences for how long things will take.