Did you not bother to check or are prices being segregated by market?

I'm in the US and when I visit the Radxa AliExpress listing (both yesterday and just now) the 32 GB variant is priced at $644 (includes import fees) plus $24 shipping. The 16 GB variant is $547 and the 8 GB is $479.

The OPi6+ 32 GB is $300 from Amazon locally or $415 plus shipping from AliExpress. (The irony of referring to Amazon as local is not lost on me.)

O6N is over $400 without any installed RAM from what I could find (making it $600 minimum given current RAM prices).

Also reading HN comments it seems the general software support picture is not great for any of these. https://news.ycombinator.com/item?id=46401499