I do like how your first sentence is “I have no idea what this means” and then follow up with more text saying how I’m wrong than my rule took.

You’re the one here advertising how much of a gigabrain move using your homebrew rules is, people are going to come with the assumption that it’s ready to use and understandable and you’re opening your creation to critique. People shouldn’t have to play 20 questions to figure out how to use your revolutionary homebrew rule, thus it is perfectly valid to criticize vaquely written rules.

If you were wondering, 1 level means -1 on your d20s.

Then why not just say that instead of the mess you wrote? Literally “you deduct your ‘exhaustion’ level from your rolls”. Also, which d20 rolls? Attack rolls, ability checks, saves, damage rolls, that one random roll your GM asks you to make to determine whether you run into a random encounter in the wilds, some of them or all of them? This is important so don’t leave your readers quessing.

That’s because I take away the old system of exhaustion completely.

So let me get this straight, it has none of the effects of exhaustion nor is it cured nor accrued in any of the ways already defined in D&D 5E? Then why is it called exhaustion when it clearly has nothing do with an already existing concept with the same name? This is needlessly confusing. Call new concepts new names.

The short rest respite is only on the FIRST short rest of the day.

And how are your readers supposed to guess this if you don’t write it out? There aren’t supposed to be any hidden rules. Besides, if you make it work literally like long rests, why not just tack it only on long rests? Rules saying there’s only one long rest in a day already exist, why not leverage that?

Anything else to ask before dishing out a critic when you don’t really understand it in the first place ? I’m honestly happy to talk, I would prefer with people asking before dishing out thought.

If your homebrew is supposedly ready for use, people should not need to ask. I’m not trying to be rude but honestly, this has a plenty of smells of a kind of “GMs first homebrew”:

• Needless complexity: That’s hell of a lot text for a supposedly simple system and you’re already leaving stuff out. The longer your rules and the more people have to puzzle things out, the less tables are going to use it.
• Reinventing the wheel: Why could this not work with the existing rules for exhaustion?
• Leaving out important details and edge cases: The unstated limit on short rests, not defining what you mean by d20 rolls, do you take a death saving throw before your action, after it or at all?

What if you rewrote all of this as simply “You can ignore the effects of being unconscious from being at 0 hp for one turn at the cost of one level of exhaustion”? You could leverage existing rules to a great degree and it would be easily understandable and digestible. It’d have minimal mechanical impact as people are almost invariably going to use their action to get more hp at which point they can just act normally. Dropping to 0 hp already renders you prone which already halves your speed or costs half your speed to get up, etc…