I do not think the core 4 was grossly overpaid by Dubas.
Tavares was a top UFA and probably could have got a little more.
Marner & Matthews have been top 10 scorers and good defensively since they came into the league
Nylander was a cut below because he was not great defensively and didn't rack up as much offensively.
But their contracts were in line with others in the league when you consider the timing of the signing, the duration, etc.
The NMCs were also common around the league.
Covid threw the cap growth off so they were cap tight to fill in the supporting cast