If you post your actual location instead of what you did, below your screen name, it helps people offering advice to know if there is a vendor close to you, or other helpful advice.
I'd use Whirlpool/Gladiator brand shelving, it assembles w/no tools, and then if you want sliding doors, install some-type of perimeter frame/closet-sliding door track, and get some hollow doors, and install 'em to the track. None of that should be very expensive. The Gladiator shelving is available in a number of sizes, by depth and length. The height overall is about 72" for the one I posted, check for the others. Just run your stiles taller, and span the distance you need with a rail wide-enough to provide space for the doors you choose. You could even make some doors from plywood, framed with 2x2's, or something similar.
4-Tier Welded Steel Garage Storage Shelving Unit (77 in. W x 72 in. H x 24 in. D)
https://www.homedepot.com/p/Gladiat...5NTPscEwlA940FsaZpxoCzzoQAvD_BwE&gclsrc=aw.ds
Home Depot $229
You could store engine blocks on each shelf, if you wanted: 8,000 lbs capacity, weight distributed. I have 5 or 6 of these, and I am very-happy with them, and I do store heavy things like engine parts on them.
One tip, cut a piece of plywood or masonite to fit inside the rails, on-top of the wire shelves, it will be much easier to remove & replace things on them. You don't need anything thick, like 3/4" plywood, you're not having it be the sole-support of the weight, the welded-wire mesh does that. You're providing a smooth surface to allow goods to slide-across the surface is all.
Two of the above units would be 156" W and you can get shorter ones. Proof of their utility (attach.)
Be aware there are different manufacturers/vendors of these types of racks, they are
not "all the same!" Some have metal shelving, and those are rated at significantly lower load ratings. The stiles and shelf rails are lighter gauge metal. There are fewer load-bearing cross-members, some have only one, instead of two, going front-to-back, below the welded wire shelf inlay.
Northern Tool sells something similar (Ironton). There are other sellers (Whalen). Costco sells them sometimes, but you have to catch them when they have them. You also want to check the specs, as the things I warned-about (differing weight limits, thinner steel members, number of supports for the welded-wire shelf inserts) may-be the case.
I just checked the Costco website, they have the Whalen two-shelf support, 2,000 lb/shelf, 77" W X 24" D X 72" H units for the same price as Home Depot is offering for the Gladiator, but you have to buy two to get that price, and it's a delivery item, I'm assuming it's 'delivery to the store, pick-up there,' all things to check-out.
https://www.costco.com/whalen-industrial-rack,-77”--x-24”--x-72”.product.100178373.html
You don't want to pay freight on these, that will probably add about 1/3 to the cost of the per-unit price.