Maybe the Practice Range Category could be "kill all the bots with 'x' number of heroes". Instead of updating the category when new heroes or changes come out you would only need 20 heroes for example and you would only need to run the category with the strategically fastest set of heroes. The way the category works now is okay too, but I thought I might suggest an idea for it.

Edit: There could also be multiple sub-categories for practice range using this way like 10 hero, 15 hero, 20 hero, etc. It would change the practice range category a lot from what it currently is but it makes it so new heroes would bring new strategies instead of changing out the category entirely.

maybe we say only the original heroes. (21)

You could have an 'original characters only' which does not update and a 'new characters only' run that does reset when new characters come out.

split it into different sub-categories (one is like the category is atm, constantly updating)

"Original Characters Only" would need updating due to updates changing the base heroes (Symm and Torb are used very differently in the run now than they were at launch) which would lead to some patches having objectively easier and faster times than others. This could be countered by having 'legacy only base characters' but that overrides the original point of the category.

There are categories that seperate new and old sym and new and old torb.

I recommended something like this for the addition of Busan to the all maps but what if we found some way to calculate an average for the individual hero and just add that to the runs released before the addition of the hero. Find some time between the fastest possible time and a slow time. This would both keep from having to update the categories and encourage people who had previous runs to rerun to improve their times.