Just thinking out loud here.

1. Have a filtered view on condition : field X = checked.

2. An Airtable automation
Trigger = running every 15 minutes
Action Step 1 = Find Records action, to find all current records having a field X checked
Action Step 2 = Script action having 12 records picked from the table randomly
Action Step 3 = Applying a check in field X on all records pick in step 2
Action Step 3 = Removing the check in field X on all records found in step 1

3. And link this filtered view to display in the Softr.io front-end?

thanks for your suggestions. looks a bit like a "brute-force" approach and uses a few thousands of automation runs every month, but is a possibility...thanks.

Also, do we know now how often/consistently NOW() updates?

re: Also, do we know now how often/consistently NOW() updates?

Hard to say I'm afraid, the only thing we know for sure is if you're using NOW() with an automation it's every hour or so.  I've seen people talk about it doing like 1-4 hours too, and so your best bet's probably @J_W1 's solution if you want to do it on Airtable's side

So I share the solution I think of using: 

I have a table with 1000 records, say blogposts. On the start page of my blog, I want to show 10 blog posts from that table, but I want those records to be displayed randomly so that if users visit my website multiple times I want them to not always see the same 10 blog posts, but be served 10 random posts...

...my solution works insofar as that visitors are very unlikely to see the same posts if they visit my page on different days, but if they reload the page within an hour or so, the same blog posts are likely to be displayed.

How: I added a column "autonumber" (assigning each record a number betwen 1 and 1000). I then have another field that takes the minutes part of NOW(), i.e. a number between 1 to 59, depending on when Airtable last updated the NOW() value for my base (using the DATETIME_FORMAT formula)

I then have that formula field calculate a range of about 20 records that moves from 1 to 1000 depending on NOQ(). When NOW() is 1, it will be the first 10 records and when NOW() is 59 it is the last 10 records.

The formula just divides the total number of records (1000) by the number of minutes (60) multiplied by the NOW() value. I use this value to filter out records if their Autonumber is not within -10 or +10 of that value and voila, whenever the the minute in NOW() changes there will be a different set of records displayed. It is true that at 14:35 hrs, it will always be the same set of records (the 35th set of records out of 60 sets of records) but unless visitors always visit my site at the same minute, they will not see the same records...

...this obviously depends on the rate at which NOW() is updated which we can't control as users.