Can't login to App Store on more than one device

Since resetting my Apple ID password I now cannot fully login to get downloads for apps etc in the App Store. I have to revert to downloading on my PC they syncing, very frustrated with this one, I've tried everything including doing a full power down and restarting, resetting my password again, checking the time is correct, all the crap that the apple cust services suggested. Absolutely drained with it all!

both are running latest ios

on the phone I tap settings/itunes & App Store /Apple ID sign out, then tap password to sign in, so far so good.

GOto to the App Store and tap any free app, click install and then all I get is the blue spinning circle

this is on wifi and cellular

when I do the above on my iPad it's slightly different

tap settings/itunes & App Store. I don't have the option to sign out because it never is signed n. I tap the password and enter it, tap the sign in and the sign in text goes from blue to grey, then back to blue. That's all it does, keep tapping away at sign in but it won't.

Apple customer services are taking me on a long circular journey of despair and quite frankly they hadn't got a clue how to understand my issue nor resolve it.

any suggestions welcomed