Best protection from thieves and fire is an insurance. You can go of course with a $2k and $5k safes that require a crew to be installed, it is a personal decision.
I keep it simple with 2, ok, ‘cabinets’ - one is slightly expensive than other but either will not survive a dedicated person with a proper cutter or torch.
If it would be up to me all my guns would be simply hanging on a wall.
As someone who sells homeowners insurance, I'd have to agree here. Check with your insurance provider as I'm giving general insurance information here so YMMV, however there are a couple of primary considerations when it comes to guns and insurance coverage:
Fire: If there's a fire loss, firearms are generally treated like any other personal property (contents). You may have to provide some evidence if you're going to claim you lost $50K or $100K in firearms just like if you're going to claim for other high valued items lost in a fire but otherwise they're pretty much treated like other contents. If your house burns down, you'll be losing a whole lot more than just your gun collection.
Theft: There are limitations for loss by theft of firearms, just like there are for other items such as jewelry, furs, etc. typically $1,500, many policies have premium endorsements that bump that amount. I just sold a policy that included $6K loss by theft of unscheduled Firearms. I have an insurance carrier that goes up to $15K.
Antiques/Collectible value: Contents, including firearms, that have antique or collectible value will need to be scheduled on a homeowners policy (this generally requires an appraisal of said item). Otherwise they'll give you the value of the item without the antique collectible value. The example I like to give is: You own a Certified autographed Babe Ruth baseball from when he was with the Red Sox, you have a Sotheby's appraisal of $XX and you have it scheduled on your homeowners policy. If your house burns down or it's stolen, you'll get the scheduled value of the item. If you don't have it scheduled, they will give you the value of a new Rawlings baseball which goes for around $5 at Walmart.
There are specialty insurance carriers that cover gun collections, there are other threads on this topic. If you have an extensive collection, this is the best bet. I don't sell that.
For me, my guns are all currently available, not antiques/collectibles. I have a monitored alarm system and video monitoring at my house, I consider that my primary defense against theft, not the safes the guns are in. If my house burns down, my homeowners insurance will cover the guns.