Download speed being weird need help

This is a real random thing that happening atm and was curious if any one has had this problem and what’s the solution.

Alright my Xbox series x is hard wired to router and I do a network test on it and it get like 50mbs down all ok, but when I got to update a game or download a game it’s soo slow like 7mbps - 3mbps or less and fluctuating never ever been like this so is the Xbox server having problems or is it my isp and I have to contact them. Any help would be appreciated thanks

:)