BREAKING: Deputy commander of Russian Navy killed in Ukrainian strike in Kursk, Russian official confirms

It also reduces the pool of available replacements because if the leadership keep getting killed, you end up with decidedly less volunteers for promotion.

Russia has lost a lot of senior officers already which will affect their overall operational effectiveness. Senior Officers need many years of training and experience and can't be easily replaced.

In a normal military this would be a pretty big deal, but Russia has long used the strategy of "keep throwing bodies at them until you win". That's also likely the reason their navy and air force are a joke as that strategy doesn't work so well when you have a finite number of craft to send those bodies on. There's a reason that Ukraine's tiny well trained military has been able to use guerrilla tactics to wipe the floor with Russia's military.

So unfortunately this is likely to make little if any difference, Putin will just find a new piece of meat to stuff into that uniform and then kick him towards the front line. What does make a huge difference though is every time they manage to destroy a piece of Russian hardware (be that a boat, plane, tank, or artillery) as Russia has a very hard time replacing those unlike their practically unlimited supply of cannon fodder.