Be careful with typical car safes. Most of them are easy to pry open, cut through, or bypass seconds. In fact, you will find many videos of victims with those safes with their guns stolen. They definitely will NOT stop a smash and grab thief.
For me, I have my own safe containers where I can keep my firearms in. They are useful when I just can't bring a firearm into an establishment or if the range is not the only place on the drive. In the Focus, I have something like this (
https://residential.amsecusa.com/product/est1014/) bolted inside the trunk. I removed the cam lever from the backup keyed lock, so if they try to bypass it that way, it won't open. My safe also comes with a power connector in case the battery dies, so it's not something I'd easily be locked out of.
For the truck, I have a pry-resistant, under-tonneau tool chest in the bed. I replaced the chintzy wafer lock with a Medeco cam lock, and I also added a latch with a spare puck lock (also Medeco core) I had laying around. It's definitely not going to stop a determined thief, but assuming they even look under the tonneau cover, I'm hoping the amount of effort required to get inside the chest won't be worth their time. It's definitely not smash and grab level of effort to get into the tool chest. We're in Texas. There are plenty of other trucks to break into.