Sure. Figure out what number divides evenly into 365 and divide that number up to convenient equal-sized units, so we can forget about leap years. Might as ell change the number of days in each month while you're at it, so they all have the same number of weeks. That's what a computer would have done, but Pope Gregory contracted it out to Renaissance astronomers instead. Only, it gets a little complicated, because solar and lunar cycles don't match up for our convenience. And we really need to know when to schedule Halloween and and ocean cruises. https://www.hermetic.ch/cal_stud/palmen/lunar13.htm

One possible solution (courtesy of Dungeons and Dragons) would be to have 12 months of 30 days, plus 5 special holidays that are not considered part of any particular month. We still need one extra day every four years, to account for leap years, so might as well make that an additional special holiday too. Then, divide each 30 day month into three 10-day "weeks". This has some advantages. For instance, the same date in each month always falls on the same day of the week, and every year is the same, too. No need to buy a new calendar each year! Now, all you need to do is to convince everybody that they should adopt this new system, Saint. Good luck with that!

At one time, the Romans used an 8 day week. But they also had a 10 month calendar, starting in March, and ending in December, with the remaining days just called "Winter". I also believe the D&D calendar model is based on a ancient one, as I remember reading about it once. The seven day week is based on the 7 known heavenly bodies known at that time (Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn*) The order appears to evolve from naming the hours of the day by order of the assumed distance of each body from the Earth, cycling through 3 of the names 3 times and the other 4 twice. The next day's first hour would start off where the last day left off. Thus each day started with a differently named hr in a cycle that lasted 7 days. Each day was then named after the hour it started with, which leads to the order we use today. *in English, the Teutonic equivalents were used for all but Saturn ( Saturn's day = Saturday) . For example, Jupiter's equivalent is Thor (Thor's day = Thursday)