Sort of a poll here: What is the largest floor drain you've ever seen in a house basement? (Manholes/sewer accesses and drains in garages do not count.) Mine would be my aunt's drain, square and about 14" wide.
I saw one once that was 30 feet long by 18 feet wide.
The one in my basement is exactly the same size as the one your aunt has. It drains to the footing drain and away from the house.
Stay with whatever is the standard floor drain entry size that matches the rest of the drainpipe system Having a larger entry floor drain hole will only mean that debris that isn't caught by the grate will likely get jammed deeper inside the drainpipe where it is hard to reach.
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