The major part of a “delay” is a matter of processing at ESA ground stations so you should revert this question to them (firstname.lastname@example.org). If you get a response, we would certainly appreciate a follow up info.
Based on our non-scientific observations cca. 50% L1C products are available on SciHub 6-12 hours after acquisition , cca 25% up to 24 hours and the rest later.
For L2A I think that ESA is waiting for most of the orbit to be processed (to L1C), before it starts with Sen2Cor. I read somewhere that delay is about 2 days after L1C.
After data is available on SciHub, it takes on average 1 hour to copy it to AWS (in/after the periods of SciHub problems this time may be prolonged)