Yes squads depth is definitely the key to win the league. Without squad depth definitely run is gonna be a short one as the team can get into trouble if you are hit by injuries. Spurs do lack in some areas but the good thing is that their injured players will be back in January so not a big worry. Long term injuries would have affected them drastically though. The only thing they need to do is do their best until their players gets recovered.
Tottenham has their three top strikers(Maddison, Richarlison, and Solomon) and a defender(Van de Ven) on injuries, to return by January is what a coach should be worried about. From now, till the time when Tottenham players are back from their injuries, up to 6 - 7 matches have been played before then. Only in their two last matches(Chelsea and Wolves), which their injured players didn't feature in, they lost it. You can imagine how many remaining matches they would play and lose to before January and you don't expect the Tottenham coach not to be worried about that from now till then(January).