> Will macOS install on a non APFS volume though?

It depends on the macOS. Only Catalina and higher (macOS 10.15) require APFS. macOS 10.14 and Mac OS X 10.x may use HFS+. That is, though High Sierra and Mojave both "want" APFS, they may be coaxed (cloned) into booting on HFS+. [0]

[0] https://apple.stackexchange.com/questions/327051/can-you-upd...