Guys if you 3g connectivity in your sim card , then use 3g connection until apple fix this issue, this issue makes problem only in when you are using 4g not in 3g, i know 3g is slow internet atleast you have make calls on 3g which is important without any call drops.....

I am using 11 pro max .In ios13 my phone was perfect , after update of ios14 the network shows no service in every few minutes, done everything with phone (include reset, format and install fresh IPSW file from itunes) after struggle of 2 month today i visit apple service centre they said there is no hardware issue . they also install ios but nothing happen , problem will still remain .. I gone switch to android ,apple is totally shit company , very bad response