Ah,logic!
Let me say I have a lot of respect for Alex Mercouris.I,m not aware of anyone who does a better job of evidence based analysis.Furthermore he always goes to great lengths to distinguish between that and his own speculations with which in the majority of cases I agree.In the case to which you refer he makes it clear he has no evidence for this other than vague rumours and conjecture to support it.
(It may or not be the case but it,s hard to understand why Assad would have refused such an offer.)
Nonetheless Alex,s view is that Assad,s failure to enter into dialogue with Erdogan did most to bring about this disaster and he points to this as an example.
The suggestion that personal antipathy towards Erdogan would lead Assad to put his country at mortal risk requires more in the way of evidence.
The unambiguous failure of Syrian,Iranian and Russian intelligence to recognise the poor state of the Syrian military and the build up of SNA and Takfiri strength in Idlib would be a better place to look for scapegoats.(I note that the Russians lost no time in dismissing the military commander in Syria)I think learning lessons is more important than seeking scapegoats.
At the moment there is much talk of "negotiations" and "ceasefires"involving Hezbollah in Lebanon and Russia in Ukraine and promoting "dialogue" with China over Taiwan and Turkiye over Syria.

With Nato who promised no eastward extension?
With Ukraine and its US/UK co-belligerents who so faithfully upheld its Minsk obligations.
With USA who accepted and ratified One China?
With genocidal apartheid Israel?
With Erdogan who endorsed the UN Security Council Resolution 2254 and Astana Process,claims no involvement with the Takfiris and whose only reason for occupying Syrian territory is to fight (US supported) Kurdish "terrorists"

These are the "bad actors" to whom I refer and whose "motivations and outcomes"hardly need identifying.

This is where my disagreement with Alex Mercouris lies.