Going through some changes on a server for a specific client and decided to document those changes so others could see if it could help them. Today, we upgraded from php 7.2 to php 7.3 in order to help reduce that time to first byte.
Server is a lamp running wordpress latest behind cloudflare.
This is after changing from php 7.2 to php 7.3:
So, as we can see, there were improvements in many of the markets we care about, so over all, the change to php 7.3 does seem to make a difference. By the way, the test for the TTFB was done with this site: https://tools.keycdn.com/performance