Hi Thomas,
Unfortunately iFixit doesn't have a lot of information on Oppo brand phones, but that doesn't mean we can't help. In looking for guides, it appears the A52 and A53 use pretty much the same procedure when replacing the screen, so here's a step by step written guide for the A52.
[link|https://www.nadiemellamagallina.com/en/manuales/smartphones-1/oppo-703/oppo-a52-1258/pantalla-completa-11210|Manuales / Oppo A52 / Fullscreen|new_window=true]
I also found a video that is specifically for the A53, so take your choice as to which one to use.
[link|https://www.youtube.com/watch?v=zsTCau87S-Q|OPPO A53 screen replacement guide / OPPO A53 phone cover removal procedure - YouTube|new_window=true]
The screen itself looks to be fairly easy to get; I'd start with places like AliExpress, eBay and Amazon and go from there. Here's one of the first ones to come up on my rather cursory search.
[link|https://www.amazon.com/Replacement-Display-PCPH2139-Digitizer-Assembly/dp/B0B883HXMJ|Amazon.com: for Oppo A53 Screen Replacement for Oppo A53/A53S LCD Display for CPH2127, CPH2131, PCPH2139, CPH2135 Digitizer Touch Screen Assembly Repair Parts Kits : Cell Phones & Accessories|new_window=true]
Hopefully that will get you going! Good luck and let us know what happens.