[Samsung Galaxy A20 Questions & Answers] FrankdonkeybrainReynolds:
(I know this doesn't help much with the OP's question but to dispel hearsay I felt it needed to be said.)

I know you don't know me, but I said I resolve peoples internet problems for a living both on supplier and consumer side and have tested this with thousands of customers but you trust a random article with very little info more and don't even bother to look at heat maps? This article has been made by someone who read a blurb about wifi, but they did get one thing right...

"A lot of electronic devices and appliances use the 2.4 GHz frequency, including microwaves, baby monitors, and garage door openers. If you have many of these in your home, or if you live in apartments or condos surrounded by other people, that 2.4 GHz band is likely to be congested, which can damage speed and signal quality."

That list is very short, it also includes lots of computer peripherals, security cameras, smart home devices, walkie talkies, radios, remote controls, wireless handsets (landlines, not mobiles) basically every wireless device you can think of uses 2.4ghz and even your microwave! all these devices on a long range signal means your neighbours devices also overlap to combine together to make the 2.4ghz band for most consumers a disaster for anything requiring more than slow speeds. This goes without even mentioning that the 2.4 ghz band only has 13 channels (3 none overlapping) to spread every wifi device out on to stop interference, in most residential are this is simply not enough. In many cases this is so bad that even next to the router people can lose 80 - 90% of their speeds or have so much interference that even loading webpages takes a long time due to the amount of data being lost.

Like I said before, even if the 5ghz DOES have shorter range, it is not so short that you have to be in the same room, what would be the point? That is a something people assume because it's a "shorter range signal" but it's not that short! the 5ghz is usually faster due to it's naturally higher data rates and more consistent due to the lack of interference from intermittent signals. Most things that interfere with 5ghz are constant and therefore it's much easier to test and know what speed you can get in other rooms away from the router, unlike the 2.4 which has the same issues with passing through anything only with a load of other issues on top too!. The 5ghz also has the advantage of having over 100 wifi channels to spread networks out on to avoid them interfering with each other, a vast upgrade to the 2.4ghz.

Here is an example of a heatmap comparing 2.4 and 5ghz but just looking at any article that goes beyond a very brief description will show you why the 2.4ghz is often so much worse than the 5ghz.

What's the Difference Between 2.4 and 5 GHz WiFi?

What do these numbers actually mean? Does it realy matter? Is one better than the other? How many questions are we going to ask in this description?

socialwifi.com

2ldr - It depends on your house and nearby networks, test both bands with different devices in different rooms and compare speeds, outside of doing more thorough testing with other apps and equipment this is the easiest and quickest way to see which will work better.