Talking about relative speed,
At the latitude of the UK "you are travelling at 950 mph as Earth rotates on its axis" but you are also "travelling at 66,700 mph as you orbit the Sun" . . . "the Solar System . . . rotates about the centre of the Galaxy, and the Galaxy is part of a local cluster that is moving towards the constellation of Virgo". [sic] "Put it all together and you are travelling at '(about)' 205 miles per second relative to the Virgo Cluster of galaxies".
Don't tell me! I know that the detail is slightly flawed (for which reason, I will not expose the source)
The rotation speed of the Solar System, and one or two other facts have been omitted, and no attempt is made to suggest any resolution of direction (which I fully understand) - but I believe that the principle is worth highlighting, in relation to the question.
P.S. Perhaps OP might have added "What is the maximum speed we can travel through space relative to
? and, maybe, "assuming, at what speed is space(time) travelling?"