Ok So I am going to modify my initial post since I wasnt clear.
My group is currently playing D&D 5th edition, we have all of the books but we find the rules to be way over complicated. Not only that, the rules conflict. They say one thing in one book and something totally different for the same rule in another.
So I am looking for suggestions for OSR games that are fantasy like D&D 5th edition but aren't. Games that are easier to play, less complicated and easier to learn the rules and without the nasty conflicts.
Honestly, most OSR games are going to fit those criteria. It's largely a question of what level of complexity you do want. Do you want base 4 classes only, or more options? Do you want classes with unique features, or just an attack bonus and some saving throws? How do you feel about Race-as-Class? Do you want a skill system? Etc. etc. and so forth.
Personally, I think that most of the games you're going to get recommended if you just base your criteria on simplicity are going to be too simple. I tend to gravitate towards games that are more based on AD&D (such as Fantastic Heroes & Witchery, Low Fantasy Gaming, Hyperborea etc.), rather than ones based on OD&D or Basic (such as OSE, Lamentations, etc.) The latter are incredibly easy to DM, but I find them underwhelming as a player.
If you're willing to step outside of the D&D ruleset, I'll put in a recommendation for the game I'm currently running: Dragon Warriors. It's a class-based fantasy game with an extremely easy to learn ruleset: MP instead of spell preparation. Only two "saving throw"-like stats, simple action economy, quick combats, etc. The only qualifiers I'll put on it are that the setting is lower fantasy than the typical D&D one, and it's pretty low on race options.
https://www.drivethrurpg.com/product/90926/Dragon-Warriors?term=serpent+king+games