I researched the power issues with certain types of SSDs before ordering. But didn't know until the end if it would work. Happy to report that's it's very possible to run ZFS on 4 drives (2TB) without issue. Key was to use lower-power NVMes (Lexar NM790 for me) and put them in a lower power state after booting:
# List, get and set power states
nvme id-ctrl /dev/nvme0 -H
nvme get-feature /dev/nvme0 -f 0x02 -H
nvme set-feature /dev/nvme0 -f 0x02 -v
I also limited the CPU a bit, but this may not be necessary, especially the second command. This can also be done in BIOS via *Performace Mode: Max Battery* and *Platform PL1/PL2 Power*.
cpupower frequency-set -g powersave
echo "1" > /sys/devices/system/cpu/intel_pstate/no_turbo