According to Guinness, "he was monitored by cinema employees during each screening". In other words, Guinness didn't verify this record. Guinness records are more PR than actual records of human achievement, you'll find a surprising number of records either weren't verified by Guinesss or were paid-for records where Guinness came up with an idea unique or specific enough for you or your company to achieve without the bother of actually tracking the record.
This record does seem plausible at least, but you're right to take Guinness with a grain of salt.
He prioritized short-length movies which allowed him to watch more in a day as he used a Regal Unlimited membership, which gives him access to every film for just $22 per month.
As per Guinness World Records, Swope saw an eye-watering 777 movies between July 2022 and July 2023, eclipsing the previous record of 715 movies held by France's Vincent Krohn.
Swope, who was raising awareness about autism, even caught multiple movies several times – including The Super Mario Bros. Movie 35 times and Thor: Love and Thunder 33 times.
I'm surprised the record's that low. It's only two a day, on average. It's a lot of time... but it's not like you have to do anything. If you pick movies with poor attendance you can just be on your phone the whole time, like anyone watching that much TV every year.