I think that giving too many choices to users who are already confused by the concept of federation and instances will enhance their paralysis of making choice due to cognitive overload (See https://en.m.wikipedia.org/wiki/Overchoice ).
I've found out kbin.social the easiest to get used to (end-user wise).
I've had better results searching through the instances themselves because Google doesn't always index the keywords on time. On caveat of this method is that if the instance doesn't have the syncing out the instance where the info is from being propagated, then this trick would not work