70+ DE safety razors on rotation: what is next?

Back to the original question. If @Home_For_Safety_Razors wants to delve into SE razors I'd say start vintage since it is cheap way to dip the toes in the proverbial waters. Good place to start is Schick Canadian Type G or Type E injectors the O.P. home pages mentions from Canada. As far as Gem style blades pretty much any of the micromatic razors, they vary in how they shave but you can get all 3 types not including sub types for about $30 - $50 USD. If you don't mind plastic razors there are a bunch of 3D printed opensource options on thingiverse if you want download the files and print them yourself or find a printer to make the razors. From there you can move towards modern and in the main $$$ artisan stuff

As far as DE goes depends the motivations. Are you looking to try new stuff because you just like using new razors or are you still searching for the one razor to rule them all.