The idea is good, implementation could be very hard.   Says you are in CA, so putting the second opening in and keeping lateral stiffness/earthquake soundness could be a real issue and will probably need some engineering consulting.

Being able to drive straight thru is a great option if you can do it.  But if also might make your garage just a driveway with a roof and you find yourself with less storage.  If it will provide vehicle access to more space, it could still be a great option. 

Also be careful, you might find you get too much breeze thru the shop.    A different option might be to build a roof structure out back with a floor and big door into the garage, have a largely outdoor shop that everything is protected by rolling stuff back in is easy.

The idea is good, implementation could be very hard.   Says you are in CA, so putting the second opening in and keeping lateral stiffness/earthquake soundness could be a real issue and will probably need some engineering consulting.

Being able to drive straight thru is a great option if you can do it.  But if also might make your garage just a driveway with a roof and you find yourself with less storage.  If it will provide vehicle access to more space, it could still be a great option. 

Also be careful, you might find you get too much breeze thru the shop.    A different option might be to build a roof structure out back with a floor and big door into the garage, have a largely outdoor shop that everything is protected by rolling stuff back in is easy.

the first two photos are my garage, so I can already drive through the breezeway carport thing to the back.
I would see adding more workspace out back with a covering which is kind of why I was thinking a double door or a single garage on the backside

I’d probably just put windows on the back wall of the garage. Horizontal sliders with the security tabs that pop-up (don’t know the proper term for these). Keep some usable floor and/or bench space.

Is the door from the garage to the breezeway a single? Might be worth upgrading to a double to use the breezeway as a covered work area?

Roof windows (fixed type) are a large source of heat. We have two about 30" x 30"in our living room and they do let in a lot of natural light which is great but also raise the temperature of the room significantly. And when it rains hard the noise drowns out the TV and you can't talk over it. That might not be an issue in a shop or garage space but something to consider if you go that route.

Here's a double door for $498 if you're looking for inexpensive.

https://www.homedepot.com/p/JELD-WEN-72-in-x-80-in-Primed-Steel-Right-Hand-Inswing-15-Lite-Glass-Stationary-Active-Patio-Door-C98388/202483598

or

https://custom.homedepot.com/custom-doors/p/Steves-Sons-Reliant-Micro-Blind-Collection-Fiberglass-Door/311789783/46552-Pre-Hung/46573-Single-Door/39977-32-x-80/46556-33-1-2-x-81-1-2-Inswing/46554-Primed-White/46563-White-Micro-Blind/45835-1-2-Lite/45143-Black-Bronze/46569-Left-Hand-Inswing/35733-4-9-16

 I haven’t found to to many options but started to look into shed doors;
https://shedsunlimited.net/replacement-storage-shed-doors-in-wood-or-raised-panel
not sure quality or how these are built. the tough-shed ones are metal frame with wood for exterior part

Id just insulate the heck outta the ceiling maybe add a whole house fan.

it's been in the 100's lately so ill probably add a mini split. I still want a door that will open up the back yard of the shop as I do power grinding out there so will be in and out a lot

Have you figured out the engineering for cutting a second large hole into the back wall? Are you going to put something like a Simpson steel movement frame in place to keep it from collapsing like a house of cards? I agree a large door(s) out the back would be nice, but it needs to be done to your counties building code.

Having my contractor do it while I'm out, think he's putting in a big header beam but will see

Think I’m gonna put a double French door in so I have that light in the winter, do you think it would be better to make the doors open out instead of the normal open in? Thinking then it wouldn’t block any work bench corner or bandsaw  (long stuff sticking out the door) that I might have there?