the only one i've seen in a comparably small form factor is the UDOO Bolt https://www.udoo.org/discover-the-udoo-bolt/

but it's an x86 system and pricey, and borderline not an SBC

memory is soldered in most of these smaller systems including the Orange Pi and it's the main price differentiator

RAM is by far the most expensive thing in those systems past the very lowest specs, this one goes from 2GiB to 8GiB AFAICS (amazon page: https://www.amazon.com/Orange-Pi-RV2-Development-Ubuntu24-04... )

the Orange Pi 5 plus comes with 16GiB but the price jumps to US$160+ or 32GiB for US$ 270+