My experience with a salvage title is off from what's been described, but it was years ago and my first car, so maybe I'm missing something, or maybe there are more state-by-state variations than I thought.
I bought a 2003 Ford Focus in 2007, from a friend of my godmother's who fixed up Focuses specifically. Mine was either the second or third my family had gotten from them. I asked if it was a salvage title and was told no, it was some minor body damage that had been repaired by getting a panel from a salvaged car. I saw a photo of the damage and it wasn't bad. The physical title didn't say anything about salvage. The state (MN) doesn't do any emissions or safety checks on passenger vehicles.
That car worked great for years, only minor maintenance things, and the only reason I wanted to trade it in was because I needed a 4-door for car seat reasons.
At the dealership, they came back saying it was a salvage title, with the KBB report proving it. They still took the trade-in, but for less than I was expecting. (I did use that as a negotiating point, so the difference wasn't huge in the end.)
The other thing to keep in mind is that salvage is often a decision made by insurance companies, and having worked for an insurance carrier for almost 20 years, I can tell you that there is a lot of variability there. A damaged car that would've been definitely salvaged in 2019 could be worth repairing in early 2021 (when used car prices spiked but before the parts crunch), and then might be back to salvage today. It's also possible to negotiate repair vs replace with the insurance company in some cases; my sister's car was about to be salvaged after an accident when my dad pointed out that the replacement would take longer than the repair and they had rental reimbursement, and the adjuster ran some more numbers and opted to repair the car.