I agree with the initial comments.

For the first one, instead of using

I'm so high on energy right now.

I think you'd be more likely to hear a native speaker say:

I'm so energized right now.

For the second one, instead of using:

Everyone at the gym is in high energy.

you might be likely to hear this idiom:

Everyone at the gym is in high gear.

M-W defines high gear as:

high gear a state of intense or maximum activity — usually used with into or in : a project in high gear.

while Macmillan says:

high gear the state of performing extremely well or extremely quickly

The term high-gear isn't necessarily equivalent to "high-energy", but I think they are roughly the same when we are talking about people working out at the gym.

I agree with the initial comments.

For the first one, instead of using

I'm so high on energy right now.

I think you'd be more likely to hear a native speaker say:

I'm so energetic right now.

For the second one, instead of using:

Everyone at the gym is in high energy.

you might be likely to hear this idiom:

Everyone at the gym is in high gear.

M-W defines high gear as:

high gear a state of intense or maximum activity — usually used with into or in : a project in high gear.

while Macmillan says:

high gear the state of performing extremely well or extremely quickly

The term high-gear isn't necessarily equivalent to "high-energy", but I think they are roughly the same when we are talking about people working out at the gym.