Good to hear it worked!
I’m with you in hoping we’ll all be able to upgrade to 8.1 (or 8.0 at the very least) soon.
At the moment, a lot of stacks are dependant on PHP 7.4. Currently, PHP 7.4 is in extended support, meaning it gets security fixes only (no new features or performance fixes). This extended support window closes at the end of November 2022, so a little over 2 months from now.
This means that developers will need to make sure their stacks can run on (at least) 8.0 by then, although 8.1 is a safer bet. 8.1 is currently the newest version.
Now, websites with 7.4 will not cease to work when support ends. In fact, there are tons of websites running on much older versions of PHP (which have all been end-of-life for a while). The big downside of running an older, unsupported version of PHP is security: if an exploit is discovered, your site could, in theory at least, be vulnerable.
To get an idea of the risks, you could take a look at the list of vulnerabilities of PHP (all versions, including the current 8.1), here.
As you can see, there are quite a few. A number of these are scored higher than a 5.0. Mostly though, the issues involve an attacker to input data somewhere that causes PHP to crash. Meaning (parts of) your website will not work as intended until PHP has been restarted.
But a few, like CVE-2021-21708 and CVE-2021-21703 enable an attacker to gain privileges to alter your site; e.g. write to files they’re not supposed to, modifying the contents of your site or install malicious files etc.
Those issues have been fixed, but if a similar issue is discovered in 7.4 after November 2022, it will not be fixed. That can be a serious problem for sites running.