Thats not what they said. The Said 5.5GB is the MINIMUM recommended speed. If the game does not run properly to then move the game to the PS5 internal SSD to run properly, Your ignoring that. This comes down to understanding the essence of a fixed closed platforms that consoles are. The common denominator for the PS5 that Exclusives will target is 5.5GB with 6 priority levels. If you want to expand then go ahead, Cerny is not lying or joking when he said comparing M.2s to the PS5 SSD is comparing apples to oranges. Since M.2s only have 2 Priority levels, it needs a little more speed to compensate, but thats on a game by game basis. If you think Sony Exclusives for the duration of the Generation are going to design games with 5.5gb read speeds and only use 2 Priority levels and ignore the other 4, because maybe 10-15% will have M.2s installed and even a smaller portion of that Pie may have a M.2 not fast enough for an exclusive game 3 years from now, again your fooling yourself.
Either move the game to the internal SSD or Buy a faster M.2 as recommended.