Most DACs or preamps or small a/v devices will use less than 1 amp, so a 2A linear power supply will be just fine. If you want to go for a 4A, it will not hurt anything.
If you have something like a video processor device (such as Lumegan) or a computer type device like Roon or Intel Nuc, then you may want a power supply that can provide more amps. The Keces P8 that provides 8A is the most powerful linear power supply I know of, but it's $900 retail! lol.
The Swagman is at a similar level to the Teradak and Zerozone power supplies. They are just fine, but not as good as Sbooster. I think one of the better supplies is the Farad Super 3, but that is also expensive at around $600 or so.