I would appreciate the “bullet-proof” solution too! Cheaper and more reliable…
Not sure if a 3 phase contactor + 1 Shelly is indeed cheaper than a S3Pro these days! All my local electrical shops are selling ABB, Hager, Schneider, Legrand etc. etc. brand DIN 3-phase contactors for anywhere from EUR 60~120 depending on spec. But I'll probably go this route all the same. Pulling up a broken borehole pump from 200m+ is a huge pain and definitely more expensive than a contactor