Set up to have build environment on NVMe ?

I have 3 drives in PC, m.2 nvme 500GB, 2.5" SSD 1TB AND 2.5" HDD 2TB. I want to set up build environment to build on the m.2 as well as using it for boot drive. The 1TB SSD is where I want to have /home and don't really care what goes on the HDD. I'm trying to utilize fastest disk space to build on to cut time as much as possible. Right now I have / on m.2 and /home on ssd and don't know if or how I can build in / partition. Building Android is such an error-prone red-headed fatherless step-child that I don't want to sync sources for half a day to a directory that isn't going to work because of a legit reason or a stupid quirk. If it will be easier to start with a fresh install of Ubuntu to set partitions with my particular goal in mind, I'm all for it. Just however it needs to be done to have a working directory to build in on m.2 but it can't have /home on m.2 because it's not big enough. I have a full system installed and only using 6% of the m.2 and 20% of ssd, if I leave 25% of m.2 unused there is still a lot of wasted high speed space sitting there while a build takes 2 hours to complete. There's got to be a better way. So, my question is how can I have /boot/efi and / on m.2, plus area for working directory for building android with make, while having /home on separate SSD ?