This is not entirely surprising.
Flash memories have many subtly different types with different performances, and there are different controllers, with different behaviours and different cache types.
It is entirely possible to have a "Pro" grade SATA 3 SSD that might, for specific use cases, outperform an NVMe SSD.
NMVe is simply the interface. Sure it is a lot faster, but budget parts in a fast case do not change the underlying features of a device.
Many SSDs use multiple flash chips. A well proportioned controller can access these chips more or less simultaneously and achieve high bulk speeds by splitting incoming data across all the devices. When reading it can read from multiple places and again get high speeds.
Small reads and writes will be difficult to speed up and will expose the speed of each individual flash device or sub-unit.
A SATA SSD might have a better flash device or controller built in. It has more space, the design considerations are subtly different, there is more space and scope for heat dissipation, the controller might be clocked higher for some reason. The controllers will also be optimised differently for their particular use cases.
NVMe drives are often designed to score big flashy "3,000 MB/s TRANSFER SPEED" numbers so that they can look good to marketing. That doesn't necessarily mean they are great at the low end as well. Sure those big numbers do help in the majority of cases as well, but as you've seen speed at the high end doesn't always translate to speed at the low end.