Direct lit is not better , it is just one of the methods LED-LCD TVs used to light up their screen.
If the technology is done right , the edge lit TV will just be as good as the direct lit .
If you think edge lit sucks , think again . Here's a hint : Sony X9300E

You are right about the edge-lit being thinner than direct lit TVs .
The TV brightness is largely attributes to the availability of an adequate dimming system and power budget of the said TV.
You mixed them up , most high end LED-LCD TVs on the market are direct lit , that's how they are able to implement full array Local dimming system into the TV which is usually more expensive . But not all direct lit TV has F.A.L.D , there are also lower budget direct-lit TVs such as the 2017's Samsung entry level MU6100.
Edge-lit TVs are often criticized due to their dimming system which is limited to controlling the LED backlights from the edge , causing a whole column of the screen to brighten up unnecessarily . There are exception to this , such as the X930E / X940E I mentioned above . And they definitely are not dimmer than the direct-lit counterparts , X930E still is one of the brightest consumer TV to date .
As a result , there is no absolute advantage between both technology . One is not definitively better than the other .
If you are looking for bright TVs , you should refer to the actual reviews  instead of being obsessed with a tech where most people don't exactly understand the difference.

get oled !

you wanna compare the brightness?
basically direct-lit is better, but thicker as compare to edge-lit

if you see most high end TV in the market, are edge-lit to maintain the thin frame

however, with current tech and R&D trying to make both of them look similar, to me a normal consumer hardly can see the brightness difference

Unfortunately both of the TVs you mentioned have fairly limited brightness , they don't do very well vs strong glare from sunlights  .
You have a few options , get a curtain or something to cover up the sunlights , or get a very bright TV  ( which can be costly )
You will need something like a Q7FN ( 5-6k for 55 inches ) .

Or avoid watching TVs during the day ...

Regardless what panel, you will have to close your glass windows with  blinds if you want nice viewing from direcr bright a
Sunlight.

And thin panels is the way to go.

IPS is good for color reproduction. Best you see it yourself in the showroom. But if not too picky, ok lah.

If the brightness too strong and watching for few hours continuous. Is it eyes will feel very tired?

No.

IPS is only good for viewing angles, that's all.