It’s not a whole lot of an exaggeration to say that “giving you a way to elegantly not do this” is one of the major reasons libraries like RxJS and frameworks like Angular even exist in the first place.
You virtually never want setTimeout in an Ionic app. You definitely never want setTimeout with a magic number, if for no other reason than you can never know if you’ve chosen the right one.
Other things I see here that are fraught with peril, should only be done if you know exactly what you are doing and why, and should be extensively commented to explain why you are deviating from normal procedure: the == operator (always use === instead) and explicit comparison against true instead of using implicit truthiness.
Finally, this post suggests what I would do instead of involving lifecycle events here at all.