I've got a problem. My venue times are all skewed. Coffee houses are only open from 6AM until noon. And some of the other venues hold SimFests at weird hours, like 1AM. This may be mod-based, but I'm darned if I know which one. None of the single mods seems to have anything to do with venues and NRAAS doesn't seem to have any relevant setting. So, is there a way I can reset them?

Do you have any version of the Ingredients Overhaul mod by any chance? That one incorporated a different mod called "Better Bars" by a prior developer that, in addition to some very nice things it does for the availability of drinks in bars, alters all the venues' opening and closing times. Though not as I recall to the odd hours you've mentioned. If you do have this though, it's not difficult to edit the venues' hours in S3PE once you find the right resource for them.

It is two files in GameplayData.package that determine venue times: Bars.xml and Venues.xml. So any mod that changes either or both of them is likely to mess with the times. However, as far as I remember, these do not affect Simfest times, which could mean that it is something completely unrelated to those two files that could have caused your issues. The times for your Coffeehouses are a bit odd and look as if something is rather changing the am/pm ratio as Coffeehouses are suppused to close at 0am (24h) while yours close at 0pm (12h).
Another file that influences Showtime venues is Proprietor.xml.

I just tried with a new game. Only CC installed were all the worlds installed from the Store, and the only mod nointro.package. I put a coffeehouse in that I'd made, and... it's open from 5AM to noon. So something appears to be wrong in my game. Which I had to reinstall about two weeks ago after my hard drive had to be wiped. The problem with Venue Times was happening before the drive problem and the reinstall, so it's not that.

I have no idea where to find the GameplayData.package or how to check it or to change it....

If this happens in your game without any mods at all (just double check again by starting a test game with a fresh user folder: remove the old The Sims folder from Documents to the Desktop and start the game; it will create a new clean folder) then modding the files in GameplayData.package won't help you anyway as there's something else amiss. I gave these file names because I thought that you were familiar with modding tuning files. If you're not it's best to not touch these files for the moment.