How can I implement this correctly where a user could search, for example, a person who speaks English and in the Europe/London timezone, and for the repeatinggroup to update on the page.
You should be able to have all three constraints in the same source expression for your Repeating Group. My only tip would be, make sure you’re on the latest Bubble version and be mindful of this important change (which would be relevant to this 3-constraint search:
Point being, some of your constraints are going to be empty until the user selects other options.
You’re probably going to want to check the “ignore empty constraints” checkbox in this case to get the desired behavior.