Using vanilla Bubble, if you want to sort your Engagements by Client name, then you’re going to have to add a field (text) on the Engagement table, to record the Client’s name to use for sorting purposes (as you can’t sort a table by a field on a linked table, at least not in vanilla Bubble)…
Alternatively, you can use the ListShifter plugin to do just that:
Sorting according to a Thing’s Thing field - Idea - Bubble Forum