Hello, according to your doubts, your MacBook's SSD is an NVMe SSD, capable of much higher speeds than any SATA-based drive.
There is no specific standard for the normal disk read-write speed. Mostly, the normal disk speed on a Mac mini, particularly recent models with SSDs, typically ranges between 2000 to 3000 MB/s for read and write speeds.
If you feel your disk speed is slow or unhealthy, you'd better check it on a more professional tool iBoysoft DiskGeeker for Mac, or use the clean junk function of it to free up more space.
This versatile tool for Mac can test the drive's read-write speed, including 2 modes for internal hard drives and 6 modes for external hard drives.
