Interesting that this channel made a video about something related to this. Except that it's not related exclusively to giant teams but more to controversial moments that might also favour host nations. Very great channel for football enthusiasts I might add.
From watching football for 30+ years, and since I am from a smaller/poorer/irrelevant country = Croatia, I have whitnessed cheating tons of times.
But, there are levels, everywhere.
For example, a champion of Croatia, Dinamo Zagreb = when they play domestic league = all refs help to Dinamo.
So, in a local league, they are absolutely the biggest/richest/most influental team politics and money wise and decisions are often atrocious in their favor.
Also, when Dinamo Zagreb plays CL qualifiers early rounds vs a team from Bosnia, Malta or Cyprus, refs often help to Dinamo.
Again, for Uefa it is better to have Zagreb in a CL than a club from Malta.
But then, if Zagreb meets AC Milan or Liverpool in the 4th qualifying round of a CL, then you will get at least one soft pen over 180 minutes for Liverpool/Arsenal/Milan.
And almost never you will get a soft pen for a small team. There won't be pens for a small team unless if it is painfully obvious and when even a ref can't close his eyes.
But then, when the same Arsenal or Ac Milan meets Barca/Real in CL semis, refs will now slightly push Barca/Real because they are tier no1.
Similar is on World cups. Tier1 are always hosts, Brazil, France, England, Germany. Biggest (Brazil) and the most richest/most influental countries from Western Europe.
If Croatia plays Malta or Bosnia in qualifiers, refs will give a slight push to Croatia and Modric.
I have to be honest, Croatia also got 10s of soft pens against Malta and Estonia when we were in troubles, let's say 0:0 in the 60th minute.
But NEVER EVER have I seen a soft pen for Malta at 0:0 in the 60th minute vs Croatia.
But if Croatia plays Brazil or France in a KO match, we are in troubles.
No soft pens for Croatia, no normal pens for Croatia. Only 100% clear pens can be awarded.
For France/Brazil/hosts on the other hand: lots of soft pens, soft free kicks. While every duel in their box is usually: foul in the attack, lol.
It doesn't mean that EVERY SINGLE match is rigged though.
For example, if Brazil meets Argentina in semis, BOTH teams are tier no1 for FIFA.
Brazil due to their history and population.
Argies due to Messi and people wanting to see Messi's story final chapter, and neutral fans want the last episode of an epic Messi-Cr7 rivalry.
So, in that match, there is no reason for FIFA to push either side. What happens = happens.
The same is with France-England. Both countries are a tier no1 for Uefa/Fifa, so refs won't interfere.
Further, it doesn't mean that tier no1 countries can't lose.
Croatia might win against Brazil, BUT ONLY if they score goals which will be impossible to cancel due to questionable offsides or foul in attacks.
So, if Croatia scores a banger from 20 meters = that's it, it can't be disallowed.
But after 1:0, they have to avoid any contact near their box and inside a box, because soft free kicks and soft pens are incoming.
So, if a smaller team can score 2-3-4 perfectly legal goals and avoid corners and duels in their box = there is a chance.
But in general, a rule of thumb might be: for smaller teams in KO matches, you start a match with 30:70 chances (refereeing) or with 0:1 score. If you can overcome that, you have a chance.
So, a smaller team/less important team usually needs to better by 2-3 goals to KO a combo of a tier 1 team helped by FIFA and refs.
1. if a big team is better = a win for big team
2. if both teams have played equal = a big team wins from a soft pen
3. if a smaller team was better for 1 goal = a big team wins or the match goes to extra time and pens
4. if a smaller team was better for 2 or 3 goals = ONLY THEN they can win a KO match late in the tournament vs tier no1 team