It is 100% going to be easy to get visa if you have a ticket.
You have no idea about the US visa system. A few years back, my B1 visa was put on hold for 6 months, just because of some administrative formalities. And many of my friends have faced difficulties with different types of visa. If you are a citizen of some of the developed nations, then it is relatively easy for you to get your hands on a US visa. But if you are from countries such as India and Pakistan, then it takes a lot of background checks and additional verifications to get a visa approved. In short, having a valid ticket doesn't guarantee you a US visa.
I have some information about the visa system in America and I visited this country once a few years ago back in 2017. Compared to many other countries and especially the other countries I visited in my life, America got harder rules for their visa system. But still, they hosted another world cup before and people had no problem with the visa system, that's why I think the government of America will not make hard rules for the visitors during the world cup.