Regurtitating that which was said by others, you could use an external launcher like ZDL/ZDoom Launcher https://zdoom.org/wiki/ZDL
Contrary to its name, it actually works with every source port.
It has a command box where you can add self-defined parameters.
The other way would be to make a parameter loading shortcut to dsda-doom.exe in the dsda-doom folder. If you make a shortcut, right click > Properties > Target.
In the Target line, behind dsdadoom.exe you can add your parameters.
An example for complevel 2 with fast monsters:
Target: C:\dsda-doom\dsda-doom.exe -complevel 2 -fast
If you use the launcher of dsda-doom (in the settings I think it's on the first or second page), you can load whatever wads you'd like and they will always have complevel 2 and fast monsters applied.
Hope this helps!