How hot your garage gets depends on several things.
Which direction your garage door faces. (Most important)
The COLOR of your garage door. (Darker colors absorb more heat than lighter colors).
Also whether your door is insulated or not.

OP - answer is "it all depends"
1) IF you need a space cooled enough to spend a lot time the garage for hobbies, wor,kshop, etc, get the mini-split
2) IF you want something just to remove stifling heat (and ventilate your attic too), get the garage fan. It will be a tad cooler than the outside air because it's in the shade plus there's a breeze. I run mine 24/7 in hot weather and I'm in the garage quite a bit.

Fans just push hot air around.

If the garage door has windows, putting a heat reflective film on thrm can help also.

I had TriLine install their garage fan on Friday so it's too soon to give a good evaluation. One issue I have is the garage door faces south. This means the afternoon sun will radiate heat through the door and which the fan has to remove. Therefore, I will need to insulate the garage door to help keep the temperature down during the day. It does appear the fan does help remove garage heat to the outside temperature faster when the sun goes down.

Does anyone have any suggestions who can insulate the garage door for me? At 81, I'm not anxious to do it myself. It would be like Joe Biden trying to do it. I have a 16' door and a cart door. About five years ago I had Munns do it for me on another home with an 18' door plus cart door for around $500. PM me with who you used what you paid.

Door Insulation
 

After insulating the doors did you need to readjust the springs to accommodate the additional weight?

I did not adjust them and no problems. The fiberglass also deadens the noise from outside.

If the garage is 90, and a fans is on, isn’t it still going to be 90 !

But, moving air cooler (to skin) than no movement when not. Now when it cold it’s still colder on skin.

An enclosed space (garage) will hold heat when there is no way to expel it. The ventilation and shade help a lot.
Imagine being out in the sun, or under a palm tree shade with a breeze. The shade and breeze helps a lot.

Does the Solar Guys unit have a fire damper?

If you have a window in the garage which most CYVs do just put a fan there pulling hot air out of the garage to the atmosphere.

Thus the reason I found a guy selling an outdoor ceiling fan for $25.

It move the air around, and when I stand under it I'm cooler. Helps when I'm messing with my car in the garage.