Any open source 60% PCBs with 4 flex cuts and daughterboard support?

I know that’s pretty specific but this is what I am looking for. There is an option for something like this that you can buy, it’s called the BIOI from Keyspresso, but it’s $70 and I could probably have something like this made for $30 if I had the files. Ideally it’d also come with a BOM. Don’t think there’s anything like this out there, not with 4 flex cuts at least but I might as well try. Thanks.