Question 3 GPUs very close together, possible heat problems or not?

[MikeBR11]

I have a ASUS ROG Zenith Extreme motherboard that takes 4 slots for GPUs.
I have an RTX 2080(Gigabyte GeForce RTX 2080 8GB Windforce) and an RTX 2060( MSI GeForce RTX 2060 6GB Ventus OC).
Both have 3 and 2 fans respectively and not a blower type but the fans are on one side with the big area(just like in the picture for the 2080 Ti below).

I want to put 1 extra RTX 2080 Ti (Asus GeForce RTX 2080 Ti 11GB ROG Strix OC--see the picture below).
I just want to ask if i can fit the 3 GPUs in there?

My main problem and question is ok they fit all 3, but by putting 3 or more, then at least 2 GPUs will be VERY close to each other so the fans of one will be just 1-2 mm away from the next GPU. Isn't this gonna create heating problems??
Shouldn't the fans have a big space for air?
Do i need a blower type of GPU necessarily to throw air from "outside" side of the card or the below GPU will have no thermal problems too?

The extra GPU i want to put is this:

 

[Traditore]

Temps will rise. Around +10C. Getting a blower 3d card won't metter much because a lot of heat comes from PCB itself and you'll have a tiny clearing for fans anyway.

How much of a problem is it? Only you know how much it bothers you and if loosing some small % of performance is crucial.

Maybe think about getting a gpu riser and postitioning the 3rd card somewhere aside in the case, 90 degree vertically.