While it's not a good idea to take anything for granted in war, there are definitely increased amounts of evidence that things are going very badly for Russia. They seem to have become entirely dependent on air strikes, there's no sign of them even building for an attack on Kyiv, and there's also evidence that the Ukrainians are now counterattacking them.
It seems that the RF were completely unable to deal with fortified urban environments, but also that they're struggling to cope with the hit-and-run tactics employed by the Ukrainians. The Americans are also starting to suggest that the Ukrainian numbers are not actually far away from the truth - which is monumental given that everyone assumed that the Ukrainian numbers were heavily exaggerated for propaganda purposes.
https://www.facebook.com/stefan.korshak has been posting daily updates around 18:00 GMT, and while he's not taking anything as truth from either side, he is repeatedly highlighting that the RF appear to be at the limits of their capabilities in terms of ground war. They are continuing to progress in the south, but both Kryvyi Rih and Dnipro have had a long time to fortify themselves. The other eyeopening thing is that it seems that Ukraine is counterattacking west of Kyiv, which is unbelievable given how most observers expected Kyiv to fall quickly.
Russia simply doesn't seem to have an answer (beyond air strikes on civilian infrastructure) for the Ukrainian tactics. The Ukrainians appear to be able to operate quite freely, and yesterday's attack on the Russian forces in Kherson Airport shows that the RF are not safe, even within territory theoretically controlled by them.
The latest tranche of military equipment from the US all but guarantees that the Russians will be attacked using guerilla tactics within occupied areas, and from what I gather, the Russians don't have the manpower to actually control entry to/from these occupied areas. There's even suggestions that the Russians are now pulling forces to Kyiv to focus on the south, because they're facing mission impossible in/around Kyiv.
It's either what you say or he's planning a significant escalation. Either way, something is amiss.
My reading of the situation is that Putin wants military leaders under control of his security forces. He will be well aware that the West can work with Russian military leaders, and there would likely be significant support from the West for a military coup that removed the FSB-cult from Russian politics. The sanctions are biting, and even Air Serbia have given up on flights to/from Belgrade to Russia.
The transponders being on suggests that someone wanted this fact to be broadcast.
IMO, the Russians will try one last surge to try and take Mariupol, but if it fails, the end of the war could well be in sight. The only question is how it ends in this situation: do the Russians unilaterally pull out (and face an almost-certain attack on the self-proclaimed LPR/DPR), or do they agree a peace settlement to return to the pre-war situation? Hard to say, I think.