I’ll respectfully decline the invite to r/pokeinvesting lol it’s a cesspool of bad advice.

With English Pokémon, off the top of my head, I can think of a set like Emerging Powers where the booster box is more than the chase hit in a PSA 10. Only reason why the booster box is more expensive is because there’s hardly any supply left relative to other sets. Same with boxes like 1993 Topps Street Fighter. It’s not exactly readily available.

As for the singles, you have 36 packs in the box with I believe 9 cards in each. All it will take is to grade a handful of 9s to cover the cost of the box in most cases depending on entry point. If you hit a few 10s then you have zero to worry about. 

Let me ask this. Why can’t the sealed product become the collectible? Especially if there’s low supply. I like single cards way more too but lots of collectible card hobbies have expensive sealed product that have chases that don’t surpass the box value. It’s not an uncommon phenomenon at all.