CPDT (Cross Platform Disk Test) is a performance benchmarking app that measures I/O speed of permanent storage (internal storage/NAND/NVMe/UFS/SD card) and system memory (RAM) of your phone. Besides Android, this app has Windows and macOS versions which makes it possible to stack you phone up against PCs, Macs, laptops (and their SSD/HDD). There's a benchmarking database with test results for all sorts of devices which is available though app. You can peek at a performance of a device of interest or compare benchmark results of your own phone against .
The project is open-source, you're welcome to visit it's page at GitHub (maxim-saplin/CrossPlatformDiskTest).
The benchmarking suite includes the following 5 test:
☻ Permanent storage tests
☺ Sequential write
☺ Sequential read
☺ Random write(4KB block)
☺ Random read (4KB block)
☻ RAM test
☺ Memory copy
Test results are given as throughput value measured in MB/s (megabytes per second).