I dont understand what the issue is between the union and league.
Why is it bad to have the 2027 season offset 2020?
So, the 2026 World Cup is in the US. The MLS season immediately following that could have a lot of buzz. MLS does not want to have to negotiate a CBA right around the World Cup - they feel the players would have an advantage in that case as the owners and league wants to ride the World Cup enthusiasm.
In June 2020, the owners got a CBA extension from 2024 to 2025 and also inserted a clause that if something unforeseen happens they can renegotiate.
In December 2020, the owners enacted the unforeseen event clause (citing Covid) and basically have demanded that the current CBA be extended to 2027. The players came back with a split the difference offer of 2026 and the owners said no, we will lock you all out and cancel the agreement we made 6 months ago. The unspoken reason being not wanting to negotiate a new CBA right in advance of the expected world cup buzz and the spoken reason presented to all of us fans being that Covid was tough financially.
This is my understanding at least.