Accommodations and Diagnosis
So, I can't speak for every country, but the situation in many cases changes remarkably when you have a formal diagnosis. The top of my list of things to do would be to not stop pushing for an answer that can be written and signed by a doctor, since until that happens, it's mostly a matter of opinion.
Protections against conditions and disabilities varies by location, but it's worth getting to know the laws in your area here.
Stay or Go
It's hard to say from an outside perspective, whether you should stay or go. If you say, you are working somewhere where they know you and your history. How much credence your current employer will put on your medical needs has a lot to do with your qualities as an employee. If you have a good boss, and a good track record, you have a good chance of advocating for change.
OTOH - in a new job you have a clean slate. They don't know you, they don't know if they can trust you, they don't know much at all. How you start this tough conversation will have a lot to do with the new company's perception of you. There's some things on your list that you may be able to get, regardless of your condition - flexible hours, work from home and well-lit areas are all pretty common desires, and may be available in a different office. However, if you are in a situation where you're falling asleep at work, and may not get a good review from someone who doesn't know the history of your hard work - then it can be problematic to change jobs when you are trying to resolve a medical condition.
Points while changing jobs
It's a tricky call to figure out how and when to bring this one up. I'd probably do it with HR somewhere close to the job offer - maybe even after, but before I formally accepted. I wouldn't want perception of my condition to impact the hiring process in a bad way.
Either way - accommodations
1) Well-lit area
This is not at all weird, and most normal people would want this. I'd think if this was the big issue, you could go right to management now and demand it. Working in total darkness isn't recommended for a number of reasons, and you don't need to have a condition here to speak up.
As a political thought - if you choose to stay, you may want to talk one on one with any colleague in the shared space who's opinions you don't know from direct statements. Often when a status quo gets going, no one wants to go against what "everyone" wants, even if "everyone" is a vocal minority. There's a difference between keeping quiet and agreeing with the status quo and you may not be so much in the minority.
2) Telework, off hours
So this is really 2 desires - being able to work from home and being able to work odd hours. In many software jobs, both are acceptable, but you'll want to talk to management. Different teams are different, and is has a lot to do with the priorities of the group in terms of communication, as well as any security/network driven concerns on whether it's possible to do you job remotely. I say that knowing that even if your company has the capacity for remote connectivity (like a VPN) sometimes software development in particular can be limited due to the need for specialized capability (configuration management, test systems, etc).
Another one that is worth a conversation with management - just be sure you are clear that you want to work remotely at odd hours and what you think you can get done with that power. Be aware of what you would and would not be able to do with this permission, for example:
- If you could come into the office, but not work remotely, does that help at all?
- If you were up and working remotely, would you then sleep through the day?
- How often would this happen? How often would it be OK with management?
- Are there options where you can be profoundly helpful? For example, is there work that is easier to do with no one around?
Having this thought out can help when you have to discuss the nuances of this arrangement.
3) I would like to have a couch or small bed in my work area where I have the option to lie down on when extreme bouts of fatigue and drowsiness happen.
I love the idea of suggesting that this is a shared resource, since it reduces any animosity and gives others a reason to get behind the idea, but I'd recommend that you advocate for something like a "privacy room" with a cot, a door that locks, and possibly other amenities. Here's a bit of reasoning:
- Good for all sorts of issues, including ones where the person making use of it does NOT want to be around others - illness with contagious symptoms, nursing mothers, migraines (noise, smell, sound can be triggers), etc.
- Publicly napping can create an image in the workplace of excessive casualness in a way that going away for 1 hour and coming back looking more rested does not.
- Avoids the potential for office inappropriate joking around.
Again, like the telework, you probably want to be ready to negotiate conditions so that they are fair for both you and the employer and other colleagues - how long would you need to rest? What can other people use it for? Who will clean it? What can you do to make up time?
At least in the US, a company is obligated to provide an accommodation only if it is reasonable and poses only a minimal burden on the business. How that gets interpreted is a legal issue, but the obvious common sense is that things like telework and a rest area are only going to work if the company has the means to offer the capability. If you have a small space for working, and there's no place to put a couch or a secondary room, then you're out of luck. If the cost of standing up remote work servers is too expensive, you're out of luck...
In many cases, an ethical company will make a counter offer, and they are within their rights as long as it actually meets your needs, so it helps to make sure you understand your own needs and limitations ahead of time. It also helps to scout around and have ideas for reasonable options that would work for you, and pose little impediment to the company.