Game freezing then speeding up multiple times
It seems that many online players have this problem. Frankly, my FC24 is unplayable as the game freezes pretty much with every pass and speeds up afterwards. My network is fine on other devices and my PS5 doesn't have a problem with other games. FC24 programming is the problem. It is broken. I know you don't care about online players because you don't get incremental payments out of them but it will show in EA25 sales unless you fix this. I certainly won't be wasting my money in September.
Do you mean a signal booster? If so, it sounds like you're on a wireless connection. What you're experiencing is extremely common with wireless connections. Can you switch to a wire instead?
Streaming uses a buffer so if there is packet loss, it's not noticed unless your connection goes out for more than several seconds. A game like FC requires a stable connection that wireless has a hard time supporting.