Need advice: How do I discover side missions in this game? (More info below)

(Spoilers) I’m currently at level 27 and just had the big battle defending my home base from Blakemore. It really feels like I’m plowing through the main quest line without activating (or even discovering) many side missions. I want to break away from the main quest every now and then.

Is there a proper way to find the blue colored side missions or should I just explore freely and happen upon them by chance?

I’m absolutely loving this game by the way. Thank you for any suggestions you can give.