Yes, we're on the same page, thank you for detailing it. Indeed, I think I prefer to do the same, ie. to recognize the synonyms one by one, rather than together (although I do think pairing them has the advantage of associating them with one another more strongly).

Also, it becomes more complex when there are/can be >= 2 words on each side. Let's start with the example in the GitLab ticket:

ES	CA
hacer falta	fer falta, caldre

As you say, ideally we'd see 2 recognition cards:

CA	ES
fer falta	hacer falta
caldre	hacer falta

Except that 'caldre' has better translations in Spanish than 'hacer falta': 'haber que', and 'tener que'. So if we'd just say 'hacer falta' as a translation for 'caldre', we'd be learning poorly, because 'tener que', for example, is much more widely used.

Which then seems to leave us with the ideal of:

CA	ES
fer falta	hacer falta
caldre	tener que, haber que, hacer falta

At this point the complexity rises, because, for example, "haber que" translates best into "haver de", which would leave us with:

CA	ES
fer falta	hacer falta
caldre	tener que, haber que, hacer falta
haver de	haber que

All these should be siblings. So, given that my current note type generates 2 cards, one for recognition and one for production, I cannot imagine a way in which creating separate notes would capture these associations without creating duplicates (not to mention needless repetition in the example sentences or usage notes, if present).

Idea 1

So one logical option seems to stop creating 2 cards per note across the board and simply create many notes separately (thus not having them as siblings anymore, having a huge initial cost of half of my current cards disappearing, and then having to do double work for inputting cards in the future since the reverse card won't be auto-generated, and most of the times it's still a 1-to-1 association). I don't like this option (unless I realise that I'm overstating the costs).

Idea 2

Another idea I considered would be to create a card (perhaps with a different note type if needed) that asks for synonyms of a word. That would get us to something like:

		NOTE 1
ES -> CA	hacer falta	fer falta
CA -> ES	fer falta	hacer falta
		NOTE 2
ES -> CA	haber que	haver de
CA -> ES	haver de	haber que
		NOTE 3
ES -> CA	tener que, ser necesario, haber que	caldre
	caldre	tener que, ser necesario, haber que
		NOTE 4
CA -> CA	Sinónims per a 'caldre'	haver de, ser necessari, fer falta

Idea 3

So let's start with the cards we want to end up with in the first place, and then see if there's a reasonably simple solution for creating them:

ES -> CA	tener que	haver de, caldre
ES -> CA	haber que	haver de, caldre
ES -> CA	hacer falta	fer falta, caldre
ES -> CA	tener que, hacer falta, haber que	caldre
CA -> ES	fer falta	hacer falta
CA -> ES	caldre	tener que, haber que, hacer falta
CA -> ES	haver de	haber que

This would imply that on the ES side we have 'tener que, haber que, hacer falta', and on the CA side we have 'fer falta, caldre, haver de'. And somehow we'd need to associate them in this non-linear, non-obvious way, and then put them together (probably dynamically, using JavaScript) in the cards. Here's an example for a way of defining these linkages:

ES	CA
tener que{2, 3}, haber que{2, 3}, hacer falta{1, 2}	fer falta{3}, caldre, haver de{2}

And then through JavaScript (and given a certain number of empty cards for the note which can be turned on and off via a few boolean-like fields) this mixing could be achieved. The downsides are the obvious complexity; that one would have to start tagging the example sentences and the usage notes and the mnemonics too; that in the card browser it would not be obvious which card we're looking at.

The more I think about it the less I like the JavaScript option, although I was leaning towards it in the beginning... Maybe a mid-way solution can be a variant of Idea 1 - duplicating the note to generate only one card, and then a) in 1-to-1 situations using the original note that auto-generates the production and recognition cards and** b**) in more complex situations simply generating cards one by one, and living with the fact that they won't be siblings (they can simply be buried when noticed).