In what way is Russia able to exert naval power right now? All they can really do is littoral sabotage with clandestine assets hence why Ukraine wants the minesweepers.

Turkey is obliged to block foreign naval interference in the Black sea, that doesn’t apply to nations that share the coast of the black sea.

I doubt they block Ukraine, and even if, I’d simply still move vessels there. What are they gonna do? Block ships passing that are meant to bolster the country that defends itself? Apart from the bad optics, Turkey also profits from Ukrainian orders