1.This question is not related to the thread issue. Suggest to ask similar questions in a common dedicated flex-table-card thread.
2.In short: the flex-table-card does not support a “tap_action” for a title. A possible workaround:
- create a vertical stack using a stack-in-card: upper - custom:button-card or a conventional button-card, lower - your flex-table-card;
- style the upper card (card-mod or native custom:button-card ways) to mimic a card’s title.