Probably the closest to a Pico in terms of being symmetrical would be the $9 Milk-V duo with two 1 GHz C906 cores (with vector units), and 64 MB RAM. It's obviously far more powerful than the Pico. And isn't available outside China yet.
Taking a step down to things that are actually available, the Sipeed M1s Dock and Pine64 Ox64 use the BL808 chip which has one 320 MHz 32 bit core, one 480 MHz 64 bit core (with vector processor), and a 3rd smaller 32 bit core that is intended to be dedicated to running the WIFI/BT. This chip also has 64 MB of on-chip RAM. The Ox64 is $6 or $8 depending on how big a flash chip (2 MB or 16 MB) it has. The M1s is a little more.
Going back to 2019, the Kendryte K210 chip has two 400 MHz 64 bit cores and 8 MB of RAM. There have been a ton of boards using it, especially from Sipeed but it's a bit more expensive than the newer chips.
There are tons of cheaper boards, but they tend to be single core and only a few KB to few hundred KB of RAM.