07 Suburban; No Oil Pressure

We’ve had this truck for a little over 11 months
now. It’s been a pain in the neck the whole
time. Recently we’ve had issues with oil leaks
and Oil pressure. We’ve changed the Rear
main, Oil pan gasket, valley pan gasket, and
put in a new oil pressure sensor and filter. Still
has a slight leak, and the other day we were
driving about 55-60 mph and the truck
dropped to 0 on the oil pressure gauge  At
the point now where we don’t know what to
do, we’ve already put $2300 in repairs into it.
Just want it fixed..