Q1, they start 50 games, but they dont finish 50 games

I sub out anyone who has 76% fitness or less immediately around minute 55-60, every game. I just played your Brescia in congested week, benched Ronaldo whole game, while took out Dybala as soon as he scored around 54th minute, Haaland starting with him, and Fabio silva coming in to score (get this kid asap).
And I have a HUGE squad I rotate heavily with (more then 22, around 24-25 plus 22 age players, and many top level depth under 22 of age). Have 6 overall CBs LOL (planned on 5, but Rugani refused to leave, and dont have in my heart to let go of Chiellini) Hakimi as backup RB, and until recently Cuadrado too, both Telles and Pellegrini backup Sandro (they play 30 games each almost for brazilians, Pellegrini 10-15), around 7-8 top quality CMs where worst player is Tonali (loaned out Zaniolo, Palacios on top of that). Winger backups that are Jao Felix, Sane, Costa and Orsolini (last one I have mainly for registration). I rotate most of all these positions alot except for key week games, except for the strikers, which I consistently start and only rest if a must. Haaland is only attacker I had thats close to their level, so he starts every 2-3 games maybe.
Your point about rotation brings up a good point, besides burden on wage bill, I could have had this huge squad entirely because alot of key backup players are under 22 still, so dont need to be registered for squad list in league (De Ligt, Romero, VanHuedsen, Pellegrini, Hakimi, Tonali, Camavinga, Haaland, Kean, Fabio Silva). But when some of them came of age soon, like Demiral just did, then it I have will have to trim the squad big time next summer

Prolly Chiellini/Bonucci, Costa or Orsolini might be gone. Plus Alex Telles sold for big fee (PSG offered 70m I said no lol), so I can give all the backup minutes to Pellegrini who seems too highly rated in this game lol.
Q2 Low crosses because IMO they are more dangerous most of the time, the wingers are really dominant cutting in, and they find with low crosses more I noticed, plus if I have high crosses it seems the fullbacks cross to eachother rather then work it into the box, its weird. But low crosses fits with the tiki taka baseline too. I still get headed goals at times from Ronaldo, Haaland and De Ligt. And because they are inverted, they go into box alot (as do my mezzala), with deep laying playmaker making last pass to overlapping wingback for the cross, and when they do to play it low, it tends to be 2 CFs, 1-2 wingers and a CM in or around the box to find with low crosses.
But if we being honest, no matter the tactic, in this ME, the most way you get goals is long balls behind defence line on counters, especially when you have top level playmakers/crazy wingers.
Q3 this is the trick, majority of the games I leave this high line, except when I face PSG/City etc in away games, every game I get couple balls behind my defence, its worth the risk, because this compact high line coupled with intense high pressing is really rewarding and good way to stop ball holder to find these long balls too often. Can maintain pressure more and hence attack to massively outscore or /keep/get back possesion more easily. Its riskier with smaller clubs, but works for me because all CBs except Bonucci are fast enough, and the 442 shape actually balance things out, especially when you have it narrow and high pressure, with CMs on support duty.
Q4 I actually like the get stuck in mode, its not absolutely necessary for high pressure to be successful, but its still effective. And I get ALOT of yellows, but almost never a red card, I think I gotten 1-3 red cards in 2 seasons, thats nothing. Also the constant flow of yellow helps me rotate my squad better when whoever gets 1 game suspension for going over 5 game limit for yellows

Its mainly the fullbacks, and I have overqualified ones.