Higher Game
Arcane
Bankruptcy means you aren't fighting wars which means you aren't making ducats from wars. It's silly to go bankrupt. It's also silly to pay for high level advisors then screw your mana by going to -100 in all mana types. Even assuming you only lose 600 mana from going bankrupt that will cost you 1800 ducats in upgrading an advisor from level 1 to level 2 to make back, and even worse if you are upgrading from level 2 to level 3. In the meantime you could have fought a war to show strength which both fucks your competition's strength, lets you take war reps from their allies, and gives you 100/100/100 mana, equivalent to around a thousand ducats at least.
You absolutely don't need to full core things. It usually doesn't even help you early game. Conquered land is going to be ~50% autonomy anyway and you will have only a little autonomy decrease (or a slight increase over time) thanks to 5% crownland, meaning stated half-cored land is producing about the same or only a little less than full cored land. The only reason to full core lands would be if you spammed reduce autonomy in all lands, which does work but is kind of annoying since constant rebels. In exchange for keeping half cores you pay 1/4th the GC cost which allows you to blob pretty much endlessly. The only things to full core early game are gold mines (which are also worth reducing autonomy on and devving to 10) and if you run out of things to spend admin on.
EDIT: Almost forgot, great trick you can do with the half-cored state thing. Whenever you get an institution you can unstate all that land to easily and cheaply embrace, then restate the next month and go right back to 50% autonomy. There's also the government reform that reduces the autonomy floor by 10% (and some other stuff like the state house and economic ideas).
I did a fresh Muscovy start after the latest patch and so far it's 1476, I have 536 development, and I took 36/43 loans for 10008 gold to help me build 24 farm estates, for all of my provinces that can take one. And this was a pretty bad start due to an independent Lithuania that allied Novgorod. I'll make some workshops and churches too and if I cut it too close then I'll sell some land or debase the currency (and if you are truly desperate you can sell a province or two) if I can't make it 10 years due to some random expense.
There's no possible war worth the manpower (or at all) that can crank out 10k+ gold by this point in the game. And I'm a single war plus annexing Perm and Pskov from hitting the GC limit anyway and I would probably already be there if I had gotten a border friction CB on Lithuania. So it really looks like nothing beats factory spam and a quick bankruptcy to gear up long term wealth.
Ok now I'm bankrupt and taking 31 gold a month in 1488 (lol) albeit with no army maintenance but I'll be loaded up for any war I want in just a few years.