Could Resignation of Boris Bondarev Indicate Internal Pressure on Putin?

Russian UN official Boris Bondarev, the Russian counselor at the Permanent Mission of the Russian Federation to the United Nations resigned his position stating, "For twenty years of my diplomatic career I have seen different turns of our foreign policy, but never have I been so ashamed of my country as on February 24 of this year."

‘Ashamed’ Russian diplomat resigns over Putin’s ‘aggressive war’

This marks a type of turn in the war. While Russia has gained some ground in Eastern Ukraine it also is coming with increased cost. They are loosing diplomatically and economically. Military strength has somewhat been tarnished. It is not guaranteed they will continue to make headway as Ukrainians create countermeasures and receive new equipment.

While this may mark a turn in internal dissention, that appears to be growing, it does not mean that Russia is down for the count. What it does mean is that he will now feel internal pressure, in addition to external pressure, to end the war. Sustained pressure that leaves a diplomatic "out" for Russia to leave Ukraine is important. 

The longer the war the more costs should mount on the Russian side until the potential gains of Ukraine are much less than the loss of achieving a lukewarm victory.

As a make it or break in historical time for Putin, he may seek to double down on efforts which will likely have mixed results. What it will likely do is increase internal pressure to remove the president from his position. High ranking officials and oligarchs may start thinking about the long term health of the  nation and devise desperate/alternative strategies with a new administration.

The question is 1.) Do they have the ability? and 2.) What is their long-term vision for the nation?

As with all things time will tell. FYI it is unsigned but appears to be true.