FORMULA to change/convert EPOCH time (aka RAW value, i.e. "1631982514") BACK into "YYYY-MM-DD HH:MM:SS" (aka Date and Time)?

Does anyone have the FORMULA to change/convert EPOCH time (aka RAW value) BACK into "YYYY-MM-DD HH:MM:SS" (I will accept "YYYY-MM-DD", given that hours, minutes, and seconds are easy to manipulate)? I would really APPRECIATE that piece of information to accomplish an action file, making it whole. Likewise, if anyone is interested in converting YYYY-MM-DD HH:MM:SS into Epoch time, check out my SINGLE line string below, as well as further details of my string, even though the placeholders are self-explanatory, via my response in this post: Convert date and time string into Raw / Epoch time - #8 by wneclass2018. Furthermore, concerning converting from EPOCH time to "YYYY-MM-DD HH:MM:SS", I thought I was on the right track, in solving for the year (aka %my_year%), using this string, "$cutright($add($div(EPOCH value'00000000',31536000),1970'00000000'),8)", but it was not 100% reliable.

CONVERT "YYYY-MM-DD HH:MM:SS" to EPOCH time (My Mp3Tag Formatted string) [using "$add(A,B,C,D,E,F,'-'G,H)"] (verified results/integers with https://www.epochconverter.com/) ➤➤

$add(%my_second%,$mul(%my_minute%,60),$mul(%my_hour%,3600),$mul($add($if($eql(365,$regexp($num(%my_year%,4),'^((?:(?<![\d])(?:(?:[1-9][0-9]{2,}|[0-9]{2})(?:[13579][0-13-57-9]|[02468][1-35-79])|(?:[13579][0-13-57-9]|[02468][1-35-79]|[1-9](?:[0-9]{1,})?(?:[13579][0-13-57-9]|[02468][1-35-79])){1}00){1}(?![\d])){1})$',365)),$sub($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp(%my_month%,'^0*[01]$',0),'^0*2$',31),'^0*3$',59),'^0*4$',90),'^0*5$',120),'^0*6$',151),'^0*7$',181),'^0*8$',212),'^0*9$',243),'^0*10$',273),'^0*11$',304),'^0*12$',334),1),$sub($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp($regexp(%my_month%,'^0*[01]$',0),'^0*2$',31),'^0*3$',60),'^0*4$',91),'^0*5$',121),'^0*6$',152),'^0*7$',182),'^0*8$',213),'^0*9$',244),'^0*10$',274),'^0*11$',305),'^0*12$',335),1)),%my_day%),86400),$mul($sub($sub(%my_year%,1900),70),31536000),$mul($div($sub($sub(%my_year%,1900),69),4),86400),'-'$mul($div($sub($sub(%my_year%,1900),1),100),86400),$mul($div($add($sub(%my_year%,1900),299),400),86400))

CONVERT "YYYY-MM-DD HH:MM:SS" to EPOCH time (ORIGINAL Formula: stackoverflow.com) ➤➤ tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 + (tm_year-70)*31536000 + ((tm_year-69)/4)*86400 - ((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400

If you do not find anyone to supply an expression in MP3tag, then you could use a CSV-export script that also includes the filename,
export the raw number and the filename,
import that CSV into a spreadsheet program,
calculate the date with one of the ready-made functions in that spreadsheet program,
export a text file with the results including the filename
import that data with Convert>Text file-Tag.