In Military Aviation History's review of that battle, a German Leopard 2 crewman was quoted that the vehicles should be spaced apart by 100m according to Bundeswehr doctrine.
Yeah, that was a good interview he did.

The thing is, the Gepards are literally irreplaceable for the time being, and we did indeed see one struck by a Lancet while redeploying back in the spring! In other words, there will be dear Gepard losses whenever they are brought up for extended periods, and out of the three dozen in Ukraine, even if the civil air defense were stripped of them all there is no way they can cover all the enablers even in the south alone.
You're right that they are irreplaceable. Just goes to show how there needs to be a good SHORAD mix that is currently not fielded in the west. I think those 'skyranger' systems look the most suitable thing to be added to the mix but there's no existing stock of spares to give to Ukraine beyond the few that went there for testing. Hope that it goes to line production soon though industry is undoubtedly waiting to see if there're significant orders. This seems a system that should be produced in the hundreds so it can be present throughout the battlefield but that's not looking to be the case for actual orders.

But the bottom line is, without Desert Storm-style air supremacy or North Africa/Kharkiv levels of density, in order to conduct ground maneuver one has to be prepared to push forward mass and absorb high initial casualties. Even against helicopters at standoff range, by being spread out in multiple robust columns while deploying smoke and moving quickly - that's another thing, in this war vehicles are usually driving at school zone speeds it seems - it is possible to make progress despite the threat.
That's one of the problems in this contested environment, the usual way to deploy smoke is with artillery and to keep up a screen of smoke for even 15 minutes involves a lot of tubes that become very vulnerable to counter battery attacks. The distances are too great for mortar based systems to provide smoke and the threat is too dangerous for ground based smoke pots to assist.

Yup, the progress is slow and against such well prepared defenses tedious. Still they're making gains and undoubtedly taxing the ability of the Russians to use their reserves.

Interesting the Wagner group fallout. I'm curious how many will be relocated to Belarus, if that's all 4k that were involved in the march north that's a brigade of potential combat power taken off the board. Curious to see if there end up being loyalty tests and purges throughout the Army ranks in the following weeks as we did see videos of Russian troops supposedly putting out pro-Wagner videos in the early hours of their taking Rostov.
Those aviation assets and aircrews lost as well as just the fact they had to apply combat power against their own forces behind their own lines is quite the toll. Having to strike your own fuel reserves to deny their use to mutineers is certainly not a high point of military power.