I need help finding out what may be causing my server to be delayed


Hello My Server is in version 1.12.2 mod pixelmon reforged 7.1.1 and I am having random delays constantly.
I will attach here the link to sponge timings, I would like a good soul to analyze and recommend me what could be done to solve my problem.
Ops: The server starts on average 3 to 5 seconds when the delay occurs.
20 minute timings: