Second image is just for context, but yeah, I’ve tried inserting a small rope like object and then tried pulling it outwards to try to get the insert back in, didn’t work and I didn’t want to break the vents. Tried pushing it into the inserts by hand to no luck. Any recommendations?

 

You may be able to circumvent removing bumper by removing fender liner to gain access from behind to reinsert, see attachment.

 

You can reach under the bumper and push the grille back in. Just feel around and pull forward towards your body. If the clips are broken then you will need a new one but they aren't expensive at all...good luck