Quests and puzzles!

It's too late to set conditions – the calculation strategy is described in post #7 – the exact number wasn't specified, but the interest is already gone, unless someone comes up with an even better strategy.

Honestly, it's a bit disappointing.
You'll ruin the interest for people now, and you're still far from the correct solution with this general strategy. The fact that you need to buy artifacts and heroes is, as they say, "obvious."
Sit down, calculate, and think about whether you can do it under the given conditions of the problem.

I've finally completed the task by initially setting 7+7 resources instead of 5+5. In this final form, it can be solved. I apologize for the several revisions. I had to remember and add a few things to make the solution more interesting. Now it can be solved!
Good luck. The solution, I assure you, won't be easy for most participants.