If you can read/write C# code and want to use the default AI you can write your own draft bot for this.

Just take a look at the MyDummyDraftBot.cs and do the following (code is italic and highlighted):

- delete method CountDeckCardNum (line 65 to 95)

- delete line 37 to 61 (so you don't have to write your own card draw logic)

- change line 27:
e.handled = true; must be e.handled = e.is_hero_choices;

- modify the return values of the method GetHeroPriority according to your preferences (the lowerest value is the best)

- compile and enjoy ;)

If you follow my steps it should work to 99%. (no 100% because I didn't test it ;) )

If you have some experience in C++ you already know Visual Studio and that's the tool to use for compiling/editing.
You need to open the HSRangerCustomDraftBot.csproj file and build as deploy job.

You might get some error because you miss the HREngine.dll.
There are two ways to fix this:
a) download HR v2.8 and use the dll from the rar-archive
b) remove the dependency to the dll (because it is outdated)
Boths ways require little searching on how to do this with Visual Studio, but it shouldn't be a big problem and I leave it to you. ;)

The synthax of C# is easy and you don't have to worry.
Just take a look at the existing code and read the error messages the compiler provides.
Make sure you close every brace you open and each statement line ends with a semicolon.

It should be an easy task because you only delete some code, replace one statement and change some numbers.
(note: you don't have to change the order of the if-blocks according to the numbers. You can go like 4-2-9-7-5-3-1-..., Just make sure every hero has its own number!)
Considering this, the dll stuff should bug you the most.