i would describe the interface on all platforms as minimalistic in a good way. in iOS there is no split tunneling (choosing which apps you want to allow to use your normal connection, essentially), but i think i remember that that option does exist from android.
for the most part you have a big connect button and a list of severs to choose from. thats what you’ll be using. a few basic “set and forget” options like PIA DNS or nah, split tunneling on most platforms, and PIA MACE (ad blocking).
as long as one doesn’t have a problem with keeping the app open on various devices they intend to be protected while using, it’s not a problem at all.
connecting a router directly to the VPN would carry the benefit of not needing the app to be open on any device. it’s slow on most routers though, especially when using OpenVPN instead of WireGuard.
i have no experience with using the WireGuard protocol from a router but i might be just barely smart enough to get that script someone linked below to run. if it were to work anywhere near as good as wireguard in the apps, i would definitely just keep using that script for the most part instead.