The young kids will have to be paid, but as long as you are signing to smart deals, then they will get paid what they are worth so its not an issue. If Girard gets paid like a top 2 D its not an issue if that is actually where his game is at. When you know a player is going to get a big raise though, like Mikko, you should factor that in though for sure. Tor is a good example of this, as they have a lot of cap this year but will need a ton of it the year after for core guys. If you don't overpay guys then you should never run into the issue without having a large surplus at a position, like the Avs may have in a few years on D.
What matters is cap efficiency as that will determine your teams talent ceiling during it competitive years. Its what makes the Mackinnon contract so insane and the Lucic deal so bad for example. Having cap space allows Avs to be flexible, for instance they are currently able to add a Tavares in UFA if they wanted to or next year if they wanted to go after a Karlsson. This biggest mistake fans often make is not realizing that doing nothing is FAR better than signing an inefficient deal (like most UFA targets) as well as thinking that change for the sake of change is a good thing. Often the teams that find the most success are the ones who the most patient and draft and develop well.
For example the Avs would be much better off doing nothing than to sign JVR to a 7x7 deal. It might not seem obvious for newer fans but its not even close.