Is the arduino sufficient for the trigger current? Min off / on voltage: 2.4/1 V (below 5V so fine), but trigger current 7.5mA / 12V - does this translate to ~32mA at 5V (below the max)?
The model controls an AC current by design. Will it work perfectly well with a DC current? (differing opinions exist online)
If it's wrong, could you recommend an alternative?
I think a SSR-10DA seems OK to control 30V DC at 4.2A.
I need to switch DC
If you only need to switch a small amount of current - 9 Amps or less, consider our compact, cost effective AC/DC SSRs.
If you need to switch more than 9 Amps, you need a serious DC SSR.
A "hockey puck" SSR, so named because of its thick shape and black color. They are specifically designed to switch either AC loads or DC loads, but never both.
"Either" being the word I liked there.
As far as I remember my English classes, "either-or" makes the discussed options mutually exclusive. Read what it says, and do not stop before reading "but never both"