Will the buoyancy force acting on the scuba diver change as he gradually sinks into the body of water to a certain depth?

Buoyancy = density of the liquid multiplied by the acceleration of gravity and by the volume of the body (or by the volume of its submerged part in the liquid).

It follows from this formula that the buoyancy force depends on:

1) On the density of the liquid.

2) From the volume of the body (or from the volume of its submerged part in the liquid).

But the buoyancy force is independent:

1) On the density of the body.

2) From the depth of immersion of the body in the liquid.

Conclusion: Buoyancy will not change as the scuba diver gradually dives into depth.