He is definitely wrong about Denayer and Tosin.
Regarding Angelino, sure, the covid climate has hit all clubs finances. That doesn't mean we didn't sell him for peanuts. Remember that Liverpool sold unproven Rhian Brewster to Sheffield for 24m during covid, and other clubs have still made decent money on sales as well (Chelsea paid alot for Havertz still). I don't think covid is FULLY enough of an excuse for how low we sold him for.
My central point stands, we are and have been shite at selling players for what their worth.