Unless you’re white it wouldn’t be great going too far back in time.
And we have no idea how dystopian the future might be so you don’t want to get locked up and have to work in some Amazon prison warehouse.
So, going back or forward in time like Ebenezer Scrooge in A Christmas Carol would probably be ideal.
Really? Am I then going the speed of light in time?
Not quite, the true invariant quantity is the magnitude of the spacetime 4 vector, which depends on rest mass.
https://en.m.wikipedia.org/wiki/Four-momentum