Theoretically the size of the Supreme Court can be increased, but realistically, I think it would be a political molotov cocktail if either party tried to do this.
The Right Wing MUST do this.
When an outsider takes the WH it should be done in the first 100 days.
FDR threatened to do it but in response the “Justices” started seeing things his way so he backed off and it never happened.
This SCOTUS needs to be fixed.