Although I don't use it myself, Reaper is a good DAW that has good accessibility with the OSARA extension installed.

https://reaperaccessibility.com/index.php/Getting_Started

While Reaper isn't free, it does have a unlimited trial period. You just need to click past a nag screen when you run it.

Musescore is free notation software. The latest version is supposed to work well with NVDA.

If you are on Windows, $1 is a free and accessible MIDI editor made by a blind guy, but it doesn't do notation and doesn't support sound banks, so you will at least need a synthesizer.

I'm also building a MIDI editor for iOS and later MacOS, but it's still far away from being ready for testing. The core functionality is fully implemented, but the user interface is still minimal and there are no editing tools yet.

On mac, for DAW you pretty much have 3 options. Reaper, pro tools or logic pro x. Logic is probably the hardest to learn with voiceover but thats just my opinion. I learned pro tools first and then logic. On windows you really only have reaper, as sonar isn't around anymore.
For notation, theres muscore, but from what I've heard its not very good yet, though that may depend on the build. I personally use sibelius from avid. It is accessible on the mac with the latest version, and there is a group of blind users on whatsapp who use it and share tips and generally help each other out.
Sibelius 5 is also accessible with jaws and windows 7, or at least jaws was what I used before the mac version was accessible, not sure about NVDA though I imagine someone's used it along the way at some point or another, again, the whatsapp group would be a good place to ask. If you want in dm me a phone number and I'll ask the admins.
A note about sibelius 5 on windows is although some things are slightly more accessible it has a few bugs and visual issues related to chord symbols for example overlapping notes that the screenreader won't tell you about. These are things that are fixed in th latest 2020.3 on the mac though, so Id recommend that, though it all depends on what your computer of choice is.
Hope this helps.

Try Musescore, or Lilypond.

Hi, I use QWS to do my midi editing. I have QWS and reaper installed and i use a programme called loop midi to connect the two. I use reaper as my host and QWS to do all the editing. Feel free to ask any questions if what i said wasn't clear enough. I am using windows 10 atnd NVDA.

As far as MIDI and a DAW, on the Mac you have Reaper, Pro tools, Logic pro X, and garage band. On the Windows side you have reaper and Sampletude from Magics. I still use Sonar 8.53 producer with the free JSonar scripts from time to time but that is well out of date now and performance can be hit or miss...

My friends and I have worked with gold wave and have found it to be fairly accessible.

logic pro works gud with v o on the mac.

Logic Pro X, Garage band are. Pro Tools should be, at least with a plugin.

Take a look at the offerings from Danceing Dots. Be prepared to pay more than a little though.

Audacity is accessible I think you can make music to a certain extent using it 

I'm not sure what exactly your looking for, but try Hokusai.
Hokusai is an audio editor, accessible on the IPhone/IPad. I think it's also on the Mac, but I'm not sure.
Hope this helps!