So the summary of the two above comments and some rough math, the s19j for $3473 will produce in revenue about $11.35 per day. If you have "free" electricity, if this were to continue, your miner would be paid off in about 306 days. The next halving will happen during those 300 days, so it will obviously extend past 306 days.
Is this summary reasonably accurate?
No. coupons reduce price to 2431 .
If you have limited free power ie you can run 1 of these free its cheap.
first 90 days you get back 1000. Next 90 days you get 500. So if it arrives feb 5 or 6 you get a lot back fast.
If you have free power.