You are correct. God created this earth in 6 literal days, then rested the 7th day, which He hallowed and sanctified, in remembrance of His creation. And yes, absolutely no gaps. Those who don’t believe that will NEVER keep the Seventh-day-Sabbath, as the 4th commandment clearly states. And, that means they bow to another’s authority, no matter how many times they claim they are born again and saved. They are in fact workers of lawlessness if they are aware, especially if they teach/instruct others to do the same. These are the same people who believe the PTR fantasy. They lack the WISDOM to discern the truth. Keeping Sunday in place of the Seventh-day-Sabbath is an abomination and those who do it deny the authority of Jesus Christ as their Creator.
Psalms 111:
10The fear of the LORD is the beginning of wisdom: a good understanding have all they that do his commandments: his praise endureth for ever.
“Cardinal Gibbons claimed that Sunday-keeping was the mark of Roman Catholic authority:
Of course the Catholic Church claims that the change was her act. It could not have been otherwise, as none in those days would have dreamed of doing anything, in matters spiritual, ecclesiastical and religious without her. This act is a mark of her ecclesiastical power and authority in religious matters.”
https://www.romeschallenge.com/downloads/RomesChallenge.pdf
God bless you for your hunger to learn more of the Word. I have the same hunger.