Im having the same problem.
Not sure what the solution is maybe its something to do with the Wireless Frequency?
Ive just logged into my router and noticed that the iPad and iPhone are on 2.4GHz whilst the Samsung devices are on 5GHz.
I am trying to get more information on this as well because I have a mesh network system and recently the signal to my iPhone and iPad is so unstable one minute im connected the next minute im not.
All my other wireless devices are ok and wired connection is ok.