It may be easier to explain using Qatar and the UAE.
About 15 years ago, the UAE bought Manchester City. They went from basically being nothing to establishing themselves as a dominant force in the English Premier League (the world's best league) and are almost certainly the best side in the world. That itself isn't the worst, as the EPL is still good, and financial regulations prevent them from completely obliterating everyone (though they aggressively look for ways to get around these rules, and are currently facing 115 charges of violating them). Before the UAE takeover, Manchester City had not won the English title since 1968. They have now won 7 in the last 12 seasons, and 5 in the last 6.
But a better example is Qatar. They bought Paris Saint-Germain in 2011. Prior to this, PSG only had 2 French titles ever, the last in 1994, and the French league was arguably the league with the most parity of the major leagues. Since then, PSG has gone on a run where they have won 9 titles in 11 seasons. They turned the league with the most parity (and which probably produces more elite players than any other country in the world) into unwatchable, uninteresting garbage. They also bought a lot of the television rights for French (and European) soccer. They are now also trying to buy Manchester United (arguably the world's most popular and expensive club). Qatar also bribed their way into hosting the 2022 World Cup (possibly the greatest sportswashing feat we have seen yet).
Recently, the Saudi's bought Newcastle. They are not yet the best team, but their turnaround has been dramatic, and it stands to reason they are only going to continue to improve rapidly. But what is more concerning than changing the fortunes of one club is the clear trend of declining competitiveness. We are quickly heading in a direction where your best chance at winning titles is basically hoping you're purchased by a petro-monarchy.
Of course, Saudi Arabia has much more money than UAE and Qatar, and they seem intent on throwing the money around and increasing their control over the sport. It's hard not to see how it could continue to increase their leverage over players and decision makers.
