Right now, there is no such thing as a completely open source laptop/desktop computer. You can have an open source operating system. You can even have an open source bios in the form of libreboot. The hardware however, is impossible to have as open source too. intel, amd, and arm all have closed source binary blobs in them. Risc-v might be an option, but frankly, I don't expect any for profit company to make their hardware accessible in any sort of intentional way.

I will never willingly put any tech inside my body that isn't entirely open source. (Just you watch, i'll make a fuss about the pacemaker tech I need to have installed in 50 years!) Since this currently excludes every major hardware company in existence, I don't expect to ever answer this question positively.