From what you have written here, unless I've misunderstood, I'm afraid I probably would resent it.
It sounds like the adjustments have gone beyond reasonable.
I understand you don't want to say the nature of your job, but it makes it hard for people to fully understand the effect is is having on others etc.
Also, I have a fairly stressful job. Sometimes work in teams, but often alone. Sometimes if I am struggling with a task I get frustrated. I will sometimes go to the loo, or make a cup of tea. Usually back at desk within 3 or 4 minutes and have another crack at the task.
How does that work for you? If you have an issue with your work which is just normal workplace frustration, not related to your ASD or selective mutism, do you recognise this and just get on with it? Or do you take 30 minute break for this as well?
I guess, ultimately, if you are getting your work done, even with the breaks, then your colleagues shouldn't be impacted. But it does sound as if they are.
Are you getting the work done? If so, then maybe this needs pointed out to the colleagues?
If not, then I'm not sure what the solution is, but I can't see that this solution would work long term.