Here's the OLED Deck specs for comparison:

APU

6 nm AMD APU

APU power: 4-15W

(which contains:)

CPU:

Zen 2 4c/8t, 2.4-3.5GHz

(up to 448 GFlops FP32)

GPU:

8 RDNA 2 CUs, 1.6GHz

(1.6 TFlops FP32)

...

RAM:

16 GB LPDDR5 on-board RAM

(6400 MT/s quad 32-bit channels)

Storage:

Steam Deck 512GB NVMe SSD

Steam Deck 1TB NVMe SSD

Both include high-speed microSD card slot

EDIT: More details

https://www.notebookcheck.net/AMD-Steam-Deck-OLED-APU-Processor-Benchmarks-and-Specs.799065.0.html

So basically, the Deck and Switch 2 are roughly inverted in compartitive hardware power... the Deck has a more powerful CPU, the Switch 2 has a more powerful GPU.

EDIT 2:

also the Deck has 33% more RAM.