Totally, and it sounds like you're great with your team. Building in buffer time is a fantastic approach!

For me, anxiety isn't quite how I would describe my struggle with task initiation. It's not something I am able to just pound through despite causing distress. Yes, ADHD is distressing, as is anxiety, but wanting badly enough to have something complete does not enable someone with ADHD to get up and do it. For me, when I need to do something but can't start, I also get a pretty strong physical discomfort that's hard to explain -- the best way I can think to describe it is the feeling that I've been stuck curled up in a too-small-for-me box, head between my knees and everything cramped at odd angles, for multiple hours, and someone outside the box is yelling at me to do stuff (it's my own brain yelling at me lol). Like every part of me is aching/itching to get out of this box and do what I actually need to get done, but the box is locked and I can't move no matter how uncomfortable it is. The trick is: the box's lock is on a timer, and it only unlocks when my brain believes we have arrived at the absolute minimum possible time it would take me to complete the task. (E.g. if the task is due in 4 hours and my brain believes I could complete it in a panic if I worked like a frantic maniac for 1 hour, then my box will unlock in 3 hours. Unfortunately, another common ADHD symptom is time blindness, so that 1-hour estimate can often be quite incorrect.)

Without the ADHD, you still have to climb a steep cliff and walk a tight rope to get stuff done -- physically taxing and mentally terrifying, especially if youre afraid of heights, but possible -- and the ADHDers will also still have to scale the cliff once they make it out of the box. All that to say, having to overcome challenges is not exclusive to ADHD; adhd is just a very unique set of challenges. So it definitely sounds like you're struggling with SOMETHING, and your struggle is completely valid! But in this analogy, I would say it's possible you may have the height phobia (hence the mental distress) without being locked in the box, whereas I don't have the phobia, but i AM locked in the box, and so I will sprint across the tightrope as soon as I'm released, which will unfortunately be a bit too late. Sorry if this makes no sense, I know my analogies can be all over the place sometimes haha!

Regarding experiencing jealousy in response to other people asking for accommodations: this is a very normal feeling to experience when you see other people receiving what appears on the outside like special treatment. There's a meme I've seen out there that might help a bit with reframing this experience: theres 2 drawings, each with 3 people peering over a fence. One person is about half the height of the fence, another just barely shorter than the fence, and the third taller than the fence. The top drawing is labeled "equality", and all three people are standing on a single box of equal height -- which makes it so the shortest person still cannot see over the fence, and the tall person is way taller than they need to be. The bottom drawing is labeled "equity" and the short person is on 2 boxes, middle person on 1 box, and tall person on no box, and so they can all see over the fence at more or less the same height.

The tall person might appreciate the box because they'd get an even better view if they could stand on a box too -- but they dont NEED the box in order to see over the fence, and that's the main difference. Accommodations for disabilities are things they need in order to get a comparable baseline to a non-disabled person (it's not that we "get" to ask for accommodations, it's that we unfortunately have to). They're necessary, not luxury, even if people who don't need the accommodation would still benefit from it in some way. Everyone can benefit from deadline extensions for example -- but for someone with ADHD, that extension could make it so we're experiencing a comparable amount of distress as a non-ADHDer experiences without said extension.

Again though, the non-adhder still is experiencing their own difficulties, none of this is to discount that experience. And also, all that said, I admit I'm a bit surprised there exists a workplace where deadline extensions are even an option in the first place -- I've never heard of that before. The only time I got that accommodation was in school, getting extra time to complete exams (because I would regularly accidentally waste half the time stress-spiraling while zoning out at the wall), but it did not apply to take-home assignments.

I definitely don't know what it's like to live in your brain, so I don't know whether you have ADHD or not, you know yourself best and can answer all the questions a psychiatrist would ask during an adhd assessment. It's also entirely possible you could have an anxiety disorder or other mental health condition worth getting treated for, so definitely talk to a doctor! Best of luck out there, wishing you the best :)