MacroDroid is a free ( upto 5 macros) automation app
Create a macro as below (name it whatever and save it)
If you want to vary the speed or pitch of reading out, change it here
Be warned that it may get to be annoying if you get many notifications or it's bothering those around you. In that case, go to the three dot menu at top right and Disable macro or decrease volume level.
You can also create a short cut to this macro from your launcher settings and select MacroDroid short cut.
Tested on Pixel 6a, Android 13.
Edit in response to comments (now deleted), but self-explanatory
The shortcut as mentioned earlier in to only easily access the macro if you wish to toggle it on/off.
You can create another macro and add it as a shortcut on your home screen to enable/disable the macro. I named it simple toggle with a reason. You can add IF conditions to flash a text message and read out if the macro is enabled or disabled state (home work for you, if you want)
It (the first macro) will NOT override DND. If you do not wish this in the constraints section of the first macro add Priority mode/ DND → Not in mode
To exclude apps like Twilight etc which are constantly in monitoring mode and are announced because of this macro - in the first macro trigger section instead of selecting all Apps choose only those you wish to be notified for. Similarly in the While/do loop select the apps you wish instead of all apps