1) In Brazil there's an entire industry of athlete's from lower divisions and agents that sells transient results that is taken in consideration in the bets.
For instance, number of corner kicks, number of fouls, yellow cards and so on. It's hard to trace it back the intention and there's a player from the National Team being investigated due to betting patterns [1].
With 80% of players earning less than USD 300 [2] when someone have the offer to take USD 10000 to receive 3 yellow cards in 5 games, it's hard to say no for those guys.
2) The problem that I see with the regulation is that not only in the sporting and social aspects (that is bad) but the money laundering and the lack of tracing in the money that goes in bet houses.
For instance, Germany has some regulation around the topic [3] but the reality if you go in some Tipico or some small bet house you can carry EUR 10000 and bet in anything, no questions asked; that's the reason why a lot of people around the world come to Germany for sports betting [4].
Anecdotally speaking, an old colleague used to manage some players in Brazilian 3rd division and he had some connections with folks in places like Germany. Before the game he already knew the bets and then just told to the players what needs to be done (e.g. I want a penalty kick after 80min, or a yellow card before 70 minutes) and after the bet being payed the agent just passed the money to the players (more or less 30%).
[1] - https://onefootball.com/de/news/fa-want-to-ban-lucas-paqueta...
[2] - https://g1.globo.com/trabalho-e-carreira/noticia/2022/12/04/...
[3] - https://cms.law/en/int/expert-guides/cms-expert-guide-to-onl...
[4] - https://n1info.rs/biznis/fatf-nemacka-raj-za-pranje-novca-go...