Your TBW will be almost exactly the same for one K35 vs two K34s.
Don’t worry, we cannot kill NVMes despite the hype. Check this thread: Has anyone here personally killed an NVME ? (NVME Endurance)
All of our NVMes are lasting far past warranted TBW. I believe that TBW causes problems for NVMEs that result in non-volatile memory loss if powered down. You may make the NVME useless for any other purpose but as you never power down while plotting this is a non-issue for Chia plotting drives. If you have a quality NVMe it will probably outlast your Chia plotting. In any case, NVMe cost is pennies per plot if the NVMe is dedicated to plotting.
There are a number of good manufacturers, but my favorite is the Samsung Plus and Pro lines for their low temperature reliability without an added heat sink and for the Samsung Magician software.