At what point will my bike become a limiting factor?

I currently ride on a 800€ gravel bike (bought new), that I use as a road bike. My average speeds for shorter rides is around 27-28km/h, and for longer rides 25-26km/h. I can still definitely improve while using this bike, but lately I have been wondering when I will need to buy a new, proper road bike, if I want to improve further. Any opinions?