Garak was the ultimate patriot - everything he did, when presented with the opportunity to do so, was to improve Cardassia.
If that meant he had to help civilian rabblerousers, he helped them, as he did in 'Profit and Loss'.
If it meant he had to help the military, he helped them, as he did in 'Way of the Warrior' (warnin' Dukat of the Klingon invasion and helpin' Dukat defend the council) and the Final Chapter (goin' with Kira & Odo to work with Damar).
He didn't pick a side or have a set agenda, except to help Cardassia as a whole, and to get back to it.
Of course "helping Cardassia" is subjective. It's whatever he currently sees as the direction Cardassia needs to be tweaked. Mix in his need for self preservation and you have a character whose agendas are not always easy to pinpoint, which is what makes him so great.