You probably got that job precisely because nobody else wanted to do it. Phone reception is draining even for neurotypicals.
If you really need the money, though, try to create your own external structure where the job offers little or none. If you can afford a tablet, I found it hugely helpful for organizing myself when midlife, mid-career, and the pandemic made me rethink the notion that I had either outgrown or been misdiagnosed with ADHD. If not, there are probably suitable note-taking apps for smartphones. The calendar app and a writing app where I make checklists and logs are my staples.
Also, vent to whomever you can and/or write a bit to organize your thoughts and come up with a plan for tackling the problem. It’s one of my oldest and best coping strategies.
As for loud noise and overreactions, I found I could train myself to react less by keeping track of overreactions (on my tablet) and reminding myself to use a stress toy instead of yelling and acting out. I started with rubber bands because that’s what I had at first, but fidget spinners and flippy chains (easy to hide in the office) work well too. My therapist, ADHD-combined and dyslexic, takes a more Aggretsuko approach and goes playing drums/singing heavy metal and for motorbike rides to let off steam.