Tear it down and do not do it again.

More information is needed. Floor plans? Exterior elevations? Sections?

Tear it down is not an option. Any ideas of different roofing material? Thank you.

Skylights alternated with LED skylight-look flat fixtures.

Paint the walls white.

Thank you.

You'll need a good ambient lighting plan no matter what. 4" recessed leds with high lumen flood bulbs would be the norm. For natural light, I'd not go forward with a framing error. I'd correct that now.

Skylights or solatubes?

What rooms are looking into this space?

This is storage space. Maybe you'll get some light if the window is south-facing and you remove the chimney and fireplace. Other than that, forget it.

More information is needed. Floor plans? Exterior elevations? Sections?

Consider reframing it since no matter what you do you will always be reminded of what it could have been. Do it now rather then later when it will be more costly. You are at the framing stage and a good time to have it corrected.

I have no clue what the reason was for this addition , where it is in relation to the home and why it is all closed in at all? YOu need lighting and lots of it so start with a good electrical plan and get a new contractor who listens to the plan. The "grill" looks like a forgotton FP . I need context for sure I see windows along the left that I assume belong to the home so now thay are completely useless for natural light into the home , seems like this was not thought out to begin with .

I am not sure I am understanding correctly, but it sounds like you are saying this area will continue to be an breezeway between the garage and the house, but will be a covered breezeway and is covered with the same roofing material as the rest of the house. You wanted just translucent plexiglass, but got a full roof.

The big issue with skylights are that so many leak, but in this case, if they leak it won't be the end of the world. If you remove the stone fireplace and let light come in from both sides and have a couple of skylights it should be a decently light and bright space and allow some light into the home.

Still not sure how the contractor messed up and built a solid roof over the entire structure if that was not what was planned.

However, the framer didn’t made enough slope in the framing, so we’re left with a flat roof unless we reframe it.

What did the plans call for? If the framer made an error in the slope change that "unless WE reframe it" to "HE should reframe it."

Light is a very big deal in the usability of this space, especially because other large windows look out on to this space. Don't fudge it forward because someone made a mistake. Revise the framing now. If the mistake is on you - calculate how much time and money this revision will take and compare that to your overall budget and timeline. Is it worth it compared to the lack of utilization that will come from a dark space?

Solatubes (also called sun tunnels) will help immensely. They provide more natural light than most ever consider. They do not leak like traditional skylights.

However, I agree that if the framer made a mistake, they should re-do it.