Surely you go out riding and go different places for a variety of terrains and obstacles. Pebbles are Cannock, wyre forest mud, kinver is sandy, Hopton castle is full of roots but it’s not something to moan about is it you ride the terrain an push yourself on that terrain. You don’t go somewhere different expecting the same thing. Otherwise why bother. If you can’t ride pebbles fast keep going an practice on them. But MTB as there called are made for all terrains so get on an ride them all. Just my opinion