The perfect OSR game is the one that you and your players enjoy in actual play.
And it probably doesn't exist.
OSR GMs tend to fall into two categories - TSR fans and Kitbashers. The TSR fans are really happy just playing Basic, 1e or 2e with little or no modification. There's zero wrong with that. In fact, I envy them as I belong in the second group.
We Kitbashers are always tinkering and rarely happy long term with any ruleset. Almost every campaign is an exercise is rewriting the game to fit our current concept of the perfect OSR game. After being a kitbasher for 4 decades, I accept my fate.
That's why my OSR game of choice is Swords & Wizardry: White Box because its so stripped down that it's like flour + water + yeast, aka the basic recipe of bread which can be modified so easily a thousand ways.