Studie Pagina Chavoerah Maqor

http://www.isawthelightministries.com/daystarts.html
https://judaism.stackexchange.com/questions/69630/how-to-reconcile-if-when-the-jewish-day-was-to-begin-at-sunset
https://judaism.stackexchange.com/questions/47635/is-there-really-evidence-that-the-rabbis-changed-the-days-beginning-from-sunris
https://thetorah.com/does-a-day-begin-in-the-evening/

http://www.isawthelightministries.com/resurrectiontime.html

G3796 opse, ὀψέ late

From the same as opiso (through the idea of backwardness); 
(adverbially) late in the day; 
by extension, after the close of the day -- (at) even, in the end.

G3798 opsios, ὄψιος, ὀψία, ὀψιον (ὀψέ) evening

From opse; late; feminine (as noun) afternoon (early eve) 
or nightfall (later eve) -- even(-ing, (-tide)).

https://pcg.church/articles/273/when-does-your-day-begin

An account in Acts can also be used to clarify the beginning of the day. “And upon the first day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight. And there were many lights in the upper chamber, where they were gathered together” (Acts 20:7-8).