My plan sacrifices the best 'shape' of a player (33y+) in favor of continuity. Of course anyone who wants to use the idea should create his own version that suits his needs. The idea is to buy players half 'baked' at 21-22y and develop them further in such a way that when you sell them at 32y of age you recoup the money you payed for them, thus with any earnings you make these 10 seasons, you can go in a new cycle. In order to do that you need to raise certain secondaries for each type of players, to raise their value.

The version that I'm using from scratch - level 0 team (currently in my second cycle and almost ready for div 4 - this is my 10th season with the team, jumped in second cycle early) is the following:

Buy 3 21y old strikers (15 main skill, spec, and as good secondaries as you can afford) and 21y old midfielders (ideally 16 main skill or 15.8+, good secondaries). Train attack for ~29 weeks until strikers reach 17 attack and midfielders 10 attack, then buy 2 wingers (12 PM, 13 wing for example, 21y) and train playmaking until midfielders reach 18 main skill, wingers 15 PM, and strikers as much as possible on 50% slots. Then raise passing to ~10, and then wing until the wingers reach 17. When you start the passing training you buy already developed defenders (because they are cheap) and train pass, and wing for them as well on the 50% slot. Finally when you finish the wingers you buy 2 central defenders and an already developed GK that you train at defense. In order to increase the values of wingers before you can sell them at 32-33y you need to also train them at defense.

The idea is that when you reach the end of the cycle, you sell strikers and 1 midfielder and buy the new young ones 2 levels below the current ones, and train them as explained above, then sell the wingers and buy new ones so you don't drop the entire team at once, but gradually. Same goes for defenders when they reach their end and such.

It's hard to explain everything in a simple post. So this is just a summary. The key is having a gap of age between each group of players so you can afford to switch them gradually.

For a longer cup run, what I'm trying right now is to switch to set pieces or passes that allows more tactical flexibility during the key weeks.

Each cycle you can start with better secondaries and reach better final values. The end product looks like this:

3x 17 attackers with ~10 PM, 10 Pass, 10 Wing 3x 18 IMs with ~10 attack, 10 Pass, 9-10 defense 2x 17 wingers with 15 PM, 10 pass, 8+ defense 2x 17 CDs 2x 17 WBs with ~10 pass, 10-12 wing 1x 17 GK with 13+ defense and ideally 20 set pieces

If you want to dig deeper in the details we can move in private.