It's not a mystery ... Opponents are based on a simple Formula.
Every NFL team plays its divisional opponents 2X, and another two Divisions entirely (on a rotating basis) ... one in each Conference.
The NFC West plays the NFC East and AFC West in '26. So the Rams and Seahawks have 14 common opponents ... including the two games against each other. Can't play with yourself ... that is frowned upon.
The only three uncommon opponents are from the other two NFC Divisions, and one AFC Division and even that is based on a Formula. Seahawks won their Division last year, so they will play the division winners in the NFC North and South (Bears and Panthers) and the AFC East (Patriots) ... while the Rams (2nd place in 2025) play their counter-parts (all the 2nd place teams) in the same three divisions (Packers, Bucs and Bills).