thnk it is lycm dt-130 it has had some "mixed" reviews but nothing to complain here function good.
in addition have received used "sonnet tempo pro" for around half the price, which can be considered also almost bargain; but this one is for two sata-based SSD, and it function aswell, but gives error with bootpicker on mp4,1/5,1, so that is bit of nuisance with the card, but with OpenCore that can be solved, since it got own bootpicker-selection.
Mojave is installed on the Tempo Pro with Sata SSD (not-raided) and function so well, that you almost don't feel the need for PciE, when compared to newer systems like Monterey, which can be are quite bit more troublesome on the MacPro4,1/5,1, and that even though have used just low-end 960GB Kingston Sata SSD.
EDIT: windows 11 have installed on another SSD entirely, have not tried if possible to use Windows AND Macos on a single PCIe based solution; it might be possible, but havent tried. there are ways to install Windows and MacOS on a single PCIe ssd, which again, havent tried, but should be perfectly, also because the MP6,1 normally just allows for one internal SSD.
The Sonnet Tempo Pro has it own firmware for Mac or Windows, and maybe also some other cards do have.
The accelsior card looking good, but i doubt i will be much faster than dt-130 or the other ones with pcie-switch mentioned on page1 on the MP5,1. but you can get more NVME installed, if need, thats good.