in the future, if using coco coir, you want 33% of the volume to be perlite, vermulite, pumice stone et al.. take your pick. large and chunky is not the best choice, but neither is fine powder for any of them. It is to improve aeration and drainage.
use a smaller pot to start, this way you don't have to deal with the headaches of watering a tiny plant in a big pot. You need to be fertilizing ever irrigation in coco to use it properly. there should be 10% runoff out the bottom each time too, which is difficult if trying to water a small area around a small plant in a big pot.
if you are not watering all the way down, it will lead to less optimal growth later on and raises risk of worse things too.
don't listen to people that say you should not transplant an autoflower, that is absurd. First, this is called "up-potting". Transplanting a plant outside invovled slicing into the roots and causing severe damage. all we do is gently place a rootball into a larger pot and sorround it with new substrate. That is not going to shock any plant. I've up-potted 300-400 or more and yet to see shock. Even had one rootball fall apart onme because i was too lazy to water first -- it was too dry to hold together and i think i bumped it needlessly -- still no shock, but was possible, admittedly and only because i fucked up in a stupid way that is 100% avoidable. Any reputable place for information will agree. check out coco for cannabis guides and dr photon's corner. Ignore the forums and most of the user-submitted stuff, lol, that's where you get information riddled with nonsense. There are so many urban myths sorrounding growing pot it's disgusting, lol.