Does it work where your decloaking at the beginning and recloak as an action to make 2 evades total or does that card only take effect once?

It only works once, because it makes you perform an evade action, and you can never perform the same action twice in the same round.

EDIT: I should also point out that this also means that you cannot use the Accelerator and perform a 'regular' Evade action in the same round.

The SPA lets you take a Free Evade action. The inability to repeat an action twice in a turn remains so you only would be able to take the Evade action once.

There's a difference between gaining a token like fel does when stressed and performing a free action, you can only perform each action on your bar once a turn but you can gain as many tokens as mechanics allow.

also worth noting that as its an action, if you are stressed and decloak, you cannot gain the evade from SPA, as you cant perform actions (even free ones) when stressed.