Guys please suggest my screen gets struck very often during the transmission  while flying even in the narrow range of 300m with 50m altitude

Dear friend, you have the same problem as many others in this forum and a lot more out of this forum!
Unfortunately, the answer to this can be given and must be given from DJI!

There are a lot of factors that could effect your transmission. First, provide your P model, FW version, are you in a city, flying in LOS? ETC... I regularly fly my P4P beywind 21000' but am in LOS and open space, no power lines, cell towers, bridges etc.