I don't think you are the right person to judge about what Paradox Dev Studios can afford - with all respect.
So they have a QA department, then we have these options:
1) QA does its job, Paradox doesnt listen -> Unprofessional
2) QA doesn't do its job, Paradox exclusively tests via multiplayer office games with 1 guy representing QA -> even more unprofessional
3) There is no QA -> unprofessional.
If Paradox wants to take on bigger projects they need to expand and get their stuff straight. If they don't do that EU5 will be again built on the very same faulty design and marketing approach as EU4 which I prefer to call EU3.5
Of course I don't know the details about their budgets. But information about sales data / frequency of play isn't too hard to get rough numbers on, and we do know that the EU4 dev team is (or at least was at one point) four members. That's an extraordinarily small team for making a game, so it stands to reason that QA would be similarly small.
Again, the fourth option you weirdly excluded:
4) QA + dev staff is too small to be able to fix things quickly enough to get the game as bug-free as you'd prefer while also developing new content to sell to keep the team in business
PDS is essentially an indie studio attached to a small but growing publisher. Most indie games are small and simple for exactly this reason. So if you want a less-buggy EU, we need either a more widely-selling EU or a simpler EU (and the former probably requires the latter, honestly).