CV1800B seems very interesting. Issue: datahsheet, i find only a preliminary chinese copy.
Here's an English copy I've had since 2023:
http://hoult.org/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdfI don't know of anything particularly wrong with it due to the "preliminary"
NB Milk-V is a company that makes boards, using chips from many different manufacturers: Cvitech (Duo), Sophgo (Pioneer, Oasis, Duo S), THead (Meles), Spacemit (Jupiter), Starfive (Mars), Eswin (Megrez)
Sophgo is a company that makes chips, primarily for bitcoin mining (they are owned by Bitmain). Their beast (as of a year ago) is a box with 18x SG2042 64 core OoO 2 GHz chips (the same as the Pioneer has one of). They bought Cvitech and developed the SG2000 from the CV1800B.
THead, part of Alibaba group, primarily designs CPU cores (C906, C908, C910, ..) but do make the odd chip such as TH1520 (C910 cores) used in a number of boards from Milk-V, Sipeed, even BeagleBoard.
StarFive JH7100 and Eswin EIC7700 are Chinese chips using SiFive CPU cores (U74, P550) designed in USA. The others named above all use THead CPU cores.