Not garage, but I use some of these inside my house to hold brooms etc. I like it better than the spring loaded ones.
https://www.amazon.ca/Command-17007-...s%2C143&sr=1-4
The straps recommended aren't bad. I just migrated to velcro cable straps because you can neatly leave it on the cable after undoing it so you won't lose the strap.
https://www.amazon.ca/Reusable-Trila...s%2C169&sr=8-5
I also saw a guy who used a system where he would staple these hook and loop cinch straps on the wall to hold things. It was kinda cool that it could hold a variety of things, but they look like ass IMO when they get too dusty, so you have to dust them off regularly with compressed air or whatever.
https://www.amazon.ca/EFFIET-Extensi...s%2C129&sr=8-6
Lumber garage shelves have always seemed odd to me. Those seemingly haven't been a hands down viable cheap option in many cases for a while now. It seems like it's kinda pricey (especially with covid spiking lumber prices) and a lot of extra work. Wire shelves on the other hand aren't too expensive and quite a bit less work than sawing and doing brackets/wall mounting etc. Plus they look nicer than raw lumber.
My buddy suggested I consider under the deck storage since I have duradeck. I might look into that as an option as well vs another shed.
If you do end up with a mezzanine, you should do a corner lift where you can use a pulley system to pull up heavy items. The platform stays up top when you don't need to use it. Comes to the floor when you do. (Can still park a car under it).