But in this case Russell was completely wrong because he interprets Descartes' cogito as a syllogism whereas it is a performative statement. Descrates' is only establishing that it's self-evident for himself that he exists, and not to assert to anyone external that he or his thoughts exist.

He’s making the point that he-ness and himself-ness is too bold a conclusion to draw from the mere existence of thoughts.

Thinking these thoughts however (from a pov of some subject) is not a "mere existence of thoughts". This imo is a classic analytic/positivistic language game.

Prove it!

(I jest, you're preaching to the choir, i.e. a first year philosophy degree drop-out who switched to do computer science to avoid having these arguments)

Which doesn't solve the problem, because it define what a "thought" is.

And besides - there are also emotions and physical sensations.

We can just lump all these together as “qualia”. “There are qualia” is the basest possible conclusion that can be drawn, as opposed to “I have qualia, therefore I am”.

Yeah I take it to mean this way too, its very strange that Descartes is controversial among eg panpsychics because of the fixation on the term 'think' - it seems pretty clear that he was just noticing that qualia exists and is the only real axiom one can rely on for any kind of self-induced philosophy of mind.