It will never be possible to get to 100%, but I principle anything below that is possible. Not just 99%, but 99.99999999% or however many you want.
Of course, it's not actually feasible, you would need galaxies worth of energy to do so.
But for something like 10% or even 50% of the speed of light, it's not even that implausible.
Badly enough, even that's not true.
We have a frame of reference given by the cosmic microwave background. When you move faster and faster at some limiting speed will create pions that will slow down the particle creating an effective slower max speed.
https://bigthink.com/starts-with-a-bang/speed-limit-below-sp...
A lot of work is done by the words "get to" which is colloquial for "accelerate".