Septic system replacement

Under contract at a new house and the seller had mentioned that the septic needed to be replaced.

Came in under asking price because we knew about this issue before hand, however we were just given the inspection report for the septic.

Basically, there is “sludge” on inlet baffle and the outer baffle couldn’t be inspected because it’s under a paver walkway. Additionally, it was noted that there is “improper pitch” in multiple sections. They also said because the field was lush, that the absorption area failed. Finally, “effluent water levels within an inch of lateral piping.”

Okay so I realize basically whole system needs replacing. Aside from being costly (50k??) what else am I looking at here? Is this a fix it and then never think about it again?

Roof is also a bit old on the house but seller said they’d give credit for some of that but not for septic.