Richard Arch

Yes and yes 👍

Its worth reading this guide first, you need to carryout the "Manual Upgrade".  Also have a read of the "Unsupported Legacy upgrades to Invision Community" section fyi.
 
Take a backup of your test environment both files and database in case you need to repeat the steps.
Run the compatibility checker, it should complain about your php version.
Disable all 3rd party applications, plugins, themes.
Switch php to version 8 or 8.1, run the compatibility checker again. Everything should ok now.
Overwrite all the files with the new package as described in the manual install.
You may need to clear cache from your ACP Support area afterwards.
 

There is another switch you can use to disable 2FA and once logged back in you can change the settings.
<?php define('DISABLE_MFA',True);  

This has been resolved in v4.7.5.

@SMen @Jim M
I've had the very same error trace also with some old images last week or so.  It turned out that a column contained the string null instead of being null.  I've no idea what caused it but our forum was upgraded from v2 to v4 back in 2019, I assumed something went wrong but maybe the latest version is using the "image_metadata" in a different way.
This sql will identify if its the same issue, it return 187 records in my case: SELECT * FROM `gallery_images` where image_metadata='null';
The fix in my case was to update them to null.

You need to change your payment options to their test/sandbox option or delete them.  Also worth a searching for NEXUS_TEST_GATEWAYS and EMAIL_DEBUG_PATH for more information.
Here is a start.