You keep on talking about the situation as it is now to explain that you couldn't have done it differently from the start. Sure you can't delete forts now, or build up force limit, or do anything. You're right, your game is pretty much doomed to be very static and opportunistic as you are behind in tech and did not expand enough. But we're trying to explain how that could have been done differently. And if you delete forts on day 1, noone attacks you. You use that money to get advisors. You use that money to build churches, to have more money later on, which you use to build manufactories. All that money sustains a huge army, with a strong force of infantry mercs so that you save up manpower. And all of a sudden that does not matter that you don't have forts, because you're not behind in miltech, and you have the biggest army in the world. That's what I'm trying to explain, the game is about the snowball. 10 ducats in 1444 can mean 500 in 1600, and 5000 in 1800.
As Vulkandrache said, that's not possible to fall behind in miltech unless you intentionally waste milpoints.
I'll explain it with figures: You generate a base amount of 3 Mil, and if you delete forts you can have at least a level 1 advisor. Even if you focus on admin and Mehmet dies instantly and is replaced by someone with 0 mil, you still generate 3 mil per month, and 4 after you killed Byzantium and gt over 50 PP. That's 48 per year, so 624 every 13 years. Techs come every 13 years and cost about 600 monarch points. So once again, you can't fall behind now that you know that war taxes and harsh treatment should be avoided. Get generals from estate, and if you have a 0 mil ruler and a 0 mil heir, I highly suggest making them generals (and disinherit the heir anyway). If not, then you can sometimes buy generals if you want. Restart and you'll see that you literally can't spend milpoints on anything.
As for falling behind in dip and admin, I'll copy what I said about it in my post (even if I understand you can't learn everything at once):
Techs play an important part in the game, and that’s something even complete beginners immediately understand. But what only more experienced players tend to realize is that not every tech is equally important. Some are clearly decisive ones in almost every scenario.
For instance, military tech 3 gives an extra 25% base morale, and military tech 4 gives an extra 20% and extra tactics. I won’t go into further details regarding how battles work, but trust me if you don’t see it, that’s insanely decisive. Miltech 15 gives a staggering 33% base morale and tactics. At the same time, Miltech 10 only gives better cavalry units and flanking range, so that’s clearly not decisive unless you rely heavily on cavalry.
Military tech is generally always good, but that’s not the case of Admin and Diplo who sometimes do literally nothing. Key admin techs are the one who unlock idea groups and the ones giving you admin efficiency, in some scenarios those giving you extra states. Key diplomatic techs are… are… pretty much nonexistent. There is one, tech 23, which unlocks Imperialism and Client States. There is one very useful in some scenarios, tech 9, and I’ll talk about it later. Else pretty much everything is irrelevant unless you fight highly contested naval battles or you play the colonial game (in which case you must rush dip7). Extra accepted culture can also be nice. I’d go so far as saying that the only reason to tech up dip is that your vassals don’t become disloyal.
Yes, you read me. Falling behind in tech is often not a problem at all so long as you hit the key techs on time. Playing in ROTW and trying to conquer massive amounts of land usually means that you will fall behind, you can’t help it unless you play too passive. That’s ok to be something like Admin 10, Dip 10, Military 15 when it’s time to get tech 15. What really matters is that you catch up at Admin 17, and Admin and Diplo 23. Players usually overcommit to techs, while only military tech is almost always relevant.
A good example is the early admin techs. Tech 5 unlocks the first idea group, and let’s assume you took Administrative as many people do. The next important tech in admin is tech 7, it brings a new idea group… which you deemed less important than admin ideas. The next one is admin 8 which gives more states, as does the finisher of admin ideas. So what’s better in most scenarios, to fill out this idea group and get admin 6, 7 and 8 after, benefiting from the discounts you’ll have to the cost of admin techs, or to care about getting these techs as fast as possible? In 99% of the scenarios the answer is pretty obvious.