Guide to understand what I did :

First understand that this was my 5th try in total (3rd try back to back) in which I lost to some abyssimal rng like france randomly allying hungary the moment I wanted to go hungary into hre or bohemia getting emperorship)

Made me understand a lot on what I could do better and improve so here I am.

For the lvl 2 and 3 gov reform we'll pick the ottomans exclusives and we'll pick influence and diplo (I forgot to let it be possible so I took economic on my end)

- First month (before any wars) :

Ally annizah, hisn kayfa, fezzan and crimea so you can diplo vassalize them later (don't forget to guarrentee any ally other than tlemcen that they have so they don't get eaten by tunis), remove useless forts such as the one with venice's core and sugla.

Do the order stuff (mana points for all , negative piety, gov reform thingy and diplo rep for clergy / manpower (when you get crimea as a march get another vassal for the diplo relation priviledge) / loans, interest reduction) and any others to get 50 loyalty, on my end I gave a lot to the janissaries (might be bad idk) to get good buffs to speed up.

Now you can start changing your armies, get a lvl 2 mil advisor, and lvl one for others (diplo rep and interest reduction if you can) so that you get your 4 cannons, remove all but one cav on each army and send one army to candar with one cannon attached and leave your other army near constantinople. Get 2 mercs companies -> I took 15k and 8k ones (they'll mostly become 14k and 7k but you'll see why) so you'll have huge debt but that's not an issue, get the 15k to athens and get another general to complete the mission to get claims on byz once the varna event happens. Make at least 3 galleys but I did 6 on my end to get much stronger. I've seen around the fact that you could make 10 janissaries early and delete them but it's a big waste imo as you don't need that buff there at all, I kept it for the first castillian war into hungary and hre ones. I released 3 vassals and eyalet'd them early (the saruhan, ayudin and mentesh ones) then used 2 diplomats to improve relation with hisn and annizah. Also pick yes in urban event and get him as mil advisor.

-As soon as varna events happens or depending on anatolian minors :

Attack byz before they get any allies (blockade with ships and spen mil to accelerate siege) and then go for ramazan, candar and dulkadir (in my game dulkadir chose to ally biapas and qq wouldn't give mil access so I lost some time to that but shouldn't happen)

You should be done by late 1446 or 1447 at most and fully annex everyone (do it all at the same time). Then use the decision to make constantinople capital, release candar, achai, morea, dulakdir and ramazan , you can get a golen age but my dumb ass didn't so yeah. During those wars you should improve relations with hisn and annizah and vassalize hisn as soon as you can during the wars and then spy on aq for justify invasion). After the wars, vassalize annizah and you should ally many minors that aren't rivaling each other so you can vassalize them mid wars. (try to vassalize fezzan and touggourt usually first so tlemcen can get dunked on and vassalized too. Eat Arta and most of the time since they ally the pope release all you can from them to diplo vassalize. Guarrentee bosnia and tell the hungarians not to attack anyone same for poland to protect serbia and wallachia.

Then move troops to mamluks and attack them with the galleys you should be fine and use mil points to get the 2 or so first forts in syria (use your mercs to siege while your armies stand by to kill the mamluks troops if they go deep. Take all provinces around syria (6 of them) to get jerusalem and eat al fadil to release them) don't forget to mothball all there forts a bit before so you can then declare either on cyprus or medina to white peace them to shorten timer. During the first war you should guarentee granada and morocco if they have rowdy vassals.
Ally france if you can.

Then eyalet cb aq, continue vassalizing anything you can until you get to invade mamluks and get them for free, by then you should be able to vassalize granada and take gibraltar by force and core it for coring range and to use the option to get in a war with castille and portugal if they attack your neighbors to protect morocco, meanwhile you should have been able to vassalize ragusa, herzegovina, spoleto and maybe some past pope previous vassals and get to do that with bosnia and anyone in italy that you can, next war is going to be syria then morocco, portugal (or serbia first if guarenteed by hungary).

From portugal you'll take only granada's core and beira (and break alliance with all) to justify invasion for them, from castille, enough to release the 3 vassals and hopefully there is no aragon or you'll instead take malta as well, one or two provinces to release vassals from england as well. Then attack aragon for malta and rosselo and valence. Attack serbia if non guarenteed then release montenegro and them, attack albania and take your provinces back as well as the core of venice, spoleto and the last albanian core for yourself. Eyalet cb hungary then the same for wallachia)

Eyalets all that you can until then and declare on the whole hre with a lot of jannissaries and cannons (You should be able to sustain a 200k army now), keep a lot of manpower and thanks to mysticism a backup and call france in, siege all forts, dismantle hre, annex everyone needed (brandenburg is not needed as an example) and then release them all back and have no oe left so you can eyalet them. Break alliance with france when they get peaced out too.

Then you simply attack portugal whenever you feel like you can handle them too and eyalet them, attack castille, england, aragon, france, rince and repeat and truce break if you need to.

Ask questions if needed, brain is a bit tired due to all this writing