Teams must always remain at or below the salary and contract caps
This rule applies for all seasons, current or future.
One of the reasons the rule is in place is to protect teams from getting into a hole which from which they can't extract themselves. This has implications for all other teams and the competition in general.
Given everyone has expiring contracts the following years shouldn't be, and haven't been, an issue. However, it applies to all seasons.
Being over the cap with players to accommodate creates a big hole to overcome. Whilst this appears to be something that could be overcome via retirements, delistings and trading, being over the salary cap to this degree is not permitted.
Reasoning:
Let's say a team has a neutral salary cap ($0 ITB) in 2026. Given an average list profile, it will have over 20 players to sign via different means. Signing those players at a minimum would put the team over the salary cap by $2M, but more realistically $4 - $5M.
That team would be looking to move on multiple $1M+ to other teams. Not many teams are likely looking to acquire this type of contract, and it would require multiple trades.
The end result is likely a non compliant team and/or a team unable to field 22 players.