Why is it always Oppo phones with the weirdest issues

Decided to take another look at 2 Oppo phones I got in a lot of 16 since neither worked, Oppo A72 4G and Oppo A5 2020, the A72 4G was salt water damaged on the inside which explained why it didn't work, and at first, I thought the A5 2020 just had a dead battery since it worked with the battery removed, but after putting a known good battery in, it still did not work.

Turns out, the FINGERPRINT SCANNER of all things had a short and was stopping the phone from booting. If you plugged it in while the phone was already on, it'd heat up to 82C (179F) in seconds and then the phone would shut off. Phone works perfectly fine without a fingerprint scanner, also weirdly the entire software is Telstra branded with not an Oppo logo in sight, but it's network unlocked!

If I were to sell it I'd probably get ~$70 AUD for it, so I might replace the fingerprint scanner if I see a new one for a reasonable price. Absolutely NO CLUE why the original fingerprint scanner broke like wtf???