I don't think the lockout on your suspension fork is very strong.
It's mostly designed for cruising the road when the trail ends, usually at the start or end of the main ride. Hitting big bumps, catching air, and generally mountain biking will destroy that lockout. It might also damage other components in the process.
I ride a hardtail but a simple 120mm fork is an absolute game changer. I only ride cross country, in response to the goofball who thinks it's only for downhill.