Multiple issues even after repair / replacement

I have the following problems with my iPhone 13 pro Max. Please note that all steps have been taken through customer support to fix them over the phone before sending for repairs.

1. Screen Flickering - This happens for 1-3 seconds lightly whenever I'm using the phone. No specific app. No specific time. No specific battery percentage. It's been happening for 2 months now. Display was changes 3 times and even sent for diagnostics but the problem occurs while on charge or even off it. Apple support advisors are asking me to screen record the problem. How do I do that when it happens for like 2-3 seconds and disappears? It takes 3 seconds to swipe down, select and then wait another 3 seconds for it to record. Have tried keeping my phone on record for sometime to catch it but unsuccessful. I've reached a dead end with support as they are either not believing me or asking me to do such a ridiculous thing. If the flickering were longer I would be able to.
2. Touch issues - At random for 20-30 seconds I will face touch issues while on charge or not. Again no specifics on when it happens as above for screen flickering. I have sent the videos to them of it and they brushed it off as 'maybe the screen was not cleaned or oil present' and the previous advisor said they could not service my request any longer.

My screen turned black and white yesterday with flashes. It's now come to a point where the screen is irritation my eyes. How do I go about this. I'm under warranty. 7 month old phone. Never dropped as good as brand new. I have so far spoken to 5 advisors many of whom do not follow up on email or respond. Sick and tired of Apple in India and their pathetic service & bad quality products for which we pay almost double for.

Just to add - when I screen record my phone and increase the brightness it does not show up. So how would a screen flicker show up?