So, you're saying that the Howard Conan stories reflected a style where Conan, when he was heroic (bought extra dice, paid Doom), always paid for it in some form later in the story.
You think that's a good model for a story set in the Hyborian Age.
You're
obsessed with the idea of "paid for it... later", as if the GM's Doom pool is some inevitable horror that will befall characters, rather than an abstraction of the natural consequences of doing risky things in dangerous places. You're also fixating on "heroic", as opposed to "reckless" or "risky" as a term to describe buying dice with Doom (because you can use other methods to do the big damn hero stuff, which you seem intent to ignore).
If someone acts recklessly, they
may suffer some consequences later. That's literally what "reckless" means - to act without regard for the consequences - so there's plenty of logic there. There's no guarantee that the GM will spend Doom on some grand deleterious effect, as opposed to something minor to keep up the pressure of the adventure.
The key to all of this is that there are numerous means by which a player character can strive and attempt difficult and dangerous tasks. The tools and resources available to them all come with some form of cost, whether that cost is action, a finite quantity, or potential consequences. It is up to the players to determine how and when they want to use those resources; a cunning and skillful group of player characters can make the most of these options and triumph against otherwise-impossible odds. You don't ever have to buy dice with Doom if you don't want to - there are other ways to get those extra dice - but it remains an option for when it happens to be necessary to get extra dice when those other options aren't available or viable, so that there's never a situation when you can't buy extra dice (though there might be situations where you
don't want to buy extra dice).
And, well, using skill and cunning and all the tools at your disposal to triumph against impossible odds... that seems quite evocative of Conan's exploits. As to how well it fits, I'm going to trust the experts we've hired to oversee the project, rather than some random angry guy on the internet. We've had no complaints so far as to the fit between system and setting.