Engine damage oil pressure faults

Seeking advise for Skoda Octavia VRS 1.8 petrol manual 2003 In which has suffered with oil pressure and contaminated oil problems.

I have only had car for six months in which initially was running good.

Please note I have listed details of the faults and procedures of repair below.

Due to being advised in that the engine has damage from the problem I am now seeking to replace engine and looking for sound advise for this due to minimal knowledge of car engines.

I have found several used engines but am concerned and not knowing if there are any other parts which were affected on my car from the faults included or required.

Some used engines come with ancillaries but most are bare engines and I want to avoid passing the oil pressure problem onto replaced engine.

FAULT DETAILS

17704 error mapped cooling system (P1296) - 18010 power supply term 30 voltage low intermittent

P0012 Advance set point not reached 16396 Bank 1 camshaft air intake.

Firstly car was running smooth when engine electronic fault warning (yellow) came on in which the codes above were found after diagnostics.

Soon after it developed intermittent problems -  TEMP was too low - OIL PRESSURE Red flashing warning kept coming on and became more frequent.

TOP ENGINE CAM - Started to rattle not always but became more frequent and noticeable at idle low speed.

 SUMP- Dropped and inspected found traces of carbon in oil and strainer was clogged.

Replaced strainer and pick up pipes were cleared not sure if they were replaced.

Oil change and filter.

This did not top the oil pressure red flashing problem and the engine fault light came back and it was again running intermittent rattle and low temp.

Next step was replacement of Temp thermostat and oil pressure switch.

This seemed like it was sorted and car ran better however soon it began sounding tappy at front idle not always but began getting more frequent and worse.

Then engine fault light came back on and oil level warning (yellow) engaged although level was okay.

Temp was too low again and not as frequent as b4 oil pressure red warning would come on at hills bends slowing down after motorways.

Had second diagnostic and 17704 was back not confirmed if the other errors were though.

Then the rattle tappy top end has become very bad and constant.

The temp sensor possibly is the cause of the 17704 error and that was plan to sort next but due to the rattle it seems like the cam shaft has suffered from the oil pressure issue and this had happened b4 i had car as in history notes on oil pressure and contaminant in oil work was done then turbo changed oil cooler and related other bits.

Final diagnostic metal fragments in oil found again cam chain knocking about engine damage.

THANKS