We "establish the Law" by staying true to our new divine nature, not by abstaining from pork or keeping one day a week holy.
The Law was made for those who walked in the flesh, and not for those who walk in the Spirit.
We don't need a Law to show us how wicked-sinful we were because we are no longer wicked or sinful.
It is written..."Knowing this, that the law is not made for a righteous man, but for the lawless and disobedient, for the ungodly and for sinners, for unholy and profane, for murderers of fathers and murderers of mothers, for manslayers,
10 For whoremongers, for them that defile themselves with mankind, for menstealers, for liars, for perjured persons, and if there be any other thing that is contrary to sound doctrine;" (1 Tim 1:9-10)
Why would the Romans or the temples destruction matter after Jesus' final sacrifice?
No other sacrifice...for sin...will ever be necessary or functional.
We don't need a temple to sacrifice via fasting, charitable work, or praising God.
We don't need a Sabbath because every day is the Lord's day.
If one wants to live under the Law in the NT, let them...but it will not make them any more holy than they were the instant they were reborn of God's seed.