Firstly, I’m glad you have it working, event tick is a fine place to test things out!
The easiest thing is probably to put the logic when it changes camera angle into whatever is changing it. Say you have a BP for “BP_TopDown”, then you’ll put the change there and have an event when it switches back.
Can also put an actor component on your main character that listens for an event called from that or something.
Basically, you don’t need to use event tick if you can put it somewhere that only fires when the perspective changes.