It doesn't work that way. Points are a function of win probability.
They are a function of the sportsbook making themselves the most money possible. The opening lines are based on statistical modeling of thousands of inputs including but not limited to previous win %, DVOA, head coach records, home field advantage, playoff record, recent wins, quality of wins, weather, injuries, rest time, proprietary rankings, etc. The lines shift based on public wagers.
For example, the early line this Sunday for Seattle vs AZ is Seattle -6.5. This means Vegas is spotting AZ 6.5 points. If Seattle only wins by a FG, the wager still loses. This is basically saying Seattle is favored, and for the wager to payout, Seattle needs to win by at least 7. The expectation is that Seattle will win this match up, and they are making it harder for bettors to win. Money line bets hardly pay anything so you have to win against this spread.
Conversely the books are not going to "spot" a team extra points that they think will lose, because they themselves would lose a ton of money when the sharks and whales bet on the team that is expected to win. In this case, Seattle.
In the Rams match up, they are effectively "spotting" Seattle 4.5 points because their expectation based on their modeling is that the Rams will win (as of right now).