Anyone find the speeds vary greatly between different devices & at different times of day?

Hello We have a router Mercusys & just added TP Deco x55 one by router in middle bedroom one in lounge to Ethernet into sky later one in daughters bedroom in attic & my office is along the hallway...

Hello Had a 4g/5g router installed Mercusys using TP Deco boosters currently got 3 well one by modem one in daughters bedroom in attic & one will be going into sky box. Seem to be getting ok speeds...