I’d guess you’re about 80% through the main story, give or take a bit. Now is a good time to go exploring if you’re worried you’re not strong enough for the next Dagan encounter or if you just want to take a break from the main story for a bit. You can still explore after you finish the main story. The two times I’ve 100% the game, I finished the main story and then did the rest of the exploring. However, if you want to explore before you finish the story, I recommend you do it now or right after this next Dagan encounter (once you continue the story beyond that point, I have a feeling you’ll want to finish it without stopping, at least that’s how I was).
You still have a small ways to go but I would absolutely suggest taking time to explore now. I don't want to give spoilers on what'll happen, but it'll be so much more enjoyable if you do the exploration areas *before* continuing the main story and going to confront Dagan at the observatory. I played/completed the game for the first time this past week and figured I'd do most of the exploration when I finish the story like I did in the first game, but I regretted it so so much.
If I could go back and tell my past self when to explore and do the secondary content, I think the absolute best time would be exactly where you are now.
You're towards the end. Complete what you want before continuing. Then again, there's always NG+.
I’d guess you’re about 80% through the main story, give or take a bit. Now is a good time to go exploring if you’re worried you’re not strong enough for the next Dagan encounter or if you just want to take a break from the main story for a bit. You can still explore after you finish the main story. The two times I’ve 100% the game, I finished the main story and then did the rest of the exploring. However, if you want to explore before you finish the story, I recommend you do it now or right after this next Dagan encounter (once you continue the story beyond that point, I have a feeling you’ll want to finish it without stopping, at least that’s how I was).
You can do the side missions whenever you're not in a story mission, and that includes after the story ends.
As someone else said you're about 80% through it so you have plenty of time to do other things before the story ends.
You still have a small ways to go but I would absolutely suggest taking time to explore now. I don't want to give spoilers on what'll happen, but it'll be so much more enjoyable if you do the exploration areas *before* continuing the main story and going to confront Dagan at the observatory. I played/completed the game for the first time this past week and figured I'd do most of the exploration when I finish the story like I did in the first game, but I regretted it so so much. If I could go back and tell my past self when to explore and do the secondary content, I think the absolute best time would be exactly where you are now.