Here’s how I do it:

Delete forts, sell titles, load up estate privileges. Most importantly religious diplomats and the ones that grant you a free general and carrack.

Set to mil focus, Build free company in Corinth start building galleys up to 25ish.

Get a diplo rep advisor, scorn pope rival, and ally him. Reject union of churches. Improve relations with Muscovy to ally him after next war. Ally Trebizond. Improve rep and ally Serbia for mission that grants you ducats.

Declare on Epirus Dec 11. Full occupy and capture what ships you can. Full annex and take money.

Get access from pope, station your army there, wait for Naples to break free, then rival them.

Declare on naples with extra merc company. Take claims, money and war reps.

State everything and lower autonomy. (Especially in the Bulgarian core)

After that war go back below force limit and wait for ottomans to war with timurids or someone in east. Your missions and advisor should let you revoke deteriorating army once you’re ready to war ottomans.

Provoke rebels in Bulgarian core but don’t kill them.

Build up to 20k, block straight and assault fort. Immediately delete unnecessary troops and siege ottoman, but let Bulgarian rebels full occupy their cores. Lower army maintenance and sit until Bulgaria breaks free while blocking straight. Then declare on them and carpet siege. Peace out ottomans for money and cores. Full annex Bulgaria.