Equal height cards in a swiper

I have a swiper containing Bootstrap cards, populated from a dynamic data source (though this is probably not relevant). I would like the cards to be of equal height but haven’t managed to achieve this yet.

I don’t think I can put the cards into a card-group which might be one way. I’ve also tried assigning class align-self-stretch to the card - no luck, nor with w-100. I’ve tried adding these classes to various parts of the card…

I would be grateful for any suggestions.

PS one thing that sort of works is assigning a fixed height to the card div. Not a very satisfactory solution.