And we are considering buying the "new" bitmain Antminer S19J.
How is your experience with the lifespan of the latter?
I've had 2 S19 95's and 4 T19's in service since February. Haven't broken one yet but they can be touchy like all the rest. I think the larger fans for the PS will help when compared to the 17 series. They are very sensitive to network or power disruptions but a reboot has fixed them every time so far. All miners are a pain in the ass at times, but so far these seem slightly better then the 17's. Nothing beats my S11's though...never repaired and still chugging along after 2.5 years.