While some of the players in City vs Barça game were starter level, most of them weren't and we can't make a guess based on this game at all, for neither teams. We need to consider how we could make sure that we can make predictions based on the games that actually matter not these.
Barcelona is a far worse team than Manchester City and everyone knows this, like if they face each other in UCL quarter finals or something, do you have a doubt about City winning that? I have zero doubt that City would be able to win easily without a trouble. This is just a friendly and I can see at least 7 players that may not play during the season, from both sides combined.
So this was just fitness check and nothing more, plus this also makes them money too, friendlies are not free tickets, people still pay tickets for this and I think it is quite nice to see something like this, allows people to have a better chance and a greater result, also means merch deals as well, like getting jerseys or whatever for people who go to these games. So this was just for the money and fitness, nothing more was intended for this game and do not make any predictions based on the 2-2 tie result and predict anything about the season.
In essence, Barcelona and Man City in yesterday's match were not serious matches for both teams who wanted to try to play some second-tier players or even young players who would be considered if their performance was very competitive. Like some teams that appeared in this friendly match always used the young players they had and when there was one young player who had good talent, later it would be seen and developed by the coach to be made a second-tier player.
Barcelona, who currently still needs a lot of quality players, will certainly always try the young players they have to get players like Lamine Yamal who can be a wonderkid.