Questions/advice needed re: buying our first 4k TV

[LeSamourai.]

Our current TV is a Sony Bravia 1080p 42-inch LCD TV from 2011. I would like to upgrade to 4k. I do not want to buy an OLED, so, my options are a full-array LED or a mini-LED TV. I'd like to buy from Sony.

After conducting some research, I'm finding it tough to make a decision. My questions:

1) Is the difference between a full-array LED and a mini-LED very big? From the retailer I want to buy from, the mini-LED costs significantly more.

2) Everywhere, I keep reading that 55" is too small and that 65" is the minimum- how true is this?
a) If I buy a 55" FALED, will I notice a significant difference from my current TV?
b) The other consideration I have is space- the 55" is just right but the 65" is bigger than our cabinet (which cannot be changed) and the edges would stick out (assuming the feet can placed within the width of the cabinet)
c) On the other hand, I do not want to buy a 55" and then feel disappointed and want to buy a 65" five years later

3) How long do these modern 4K TVs last? Our current TV has lasted quite long for a not-too-high price (£600-700). It would be very disappointing to have to spend £1000+ every 10 years

4) Based on my research, a lot of modern TVs do not have a headphone jack (OLEDs especially). Do Sony FALEDs/mini-LEDs have headphone jacks? If not, how can I use headphones with such TVs?

5) Is there a risk of burn-in with:
a) FALED TVs
b) mini-LED TVs?


I hope you guys can help me as I have spent ages trying to come to a decision.

Thank you, friends.