Our wifi signal is bad

I live in the country in southern ireland with my 4 teenage girls and husband-their phones are now interfering with family time, home work etc.   Always a fight about the usage of phones. Is it possible and what would you recommend for a 4000sq foot house size for a mobile cell jammer for 3g and 4g, i suppose 5g will be coming shortly.  if i could get something that i could turn on and off when it suited us.   Our wifi signal is bad and the girls end up on their 3g most times but when the wifi signal is good they use the 4g-they are with Vodafone, i don’t know what frequency that is.