I didn't really feel like going through phpSwitcher plugin, so I went from PHP 7.1 to 7.4, and made a few modifications to imscp that allowed `--reconfigure php` to finish successfully, and so far, the panel, all sites, backups, and other daemon operations, etc., appear to be working properly on 7.4.21 (with ionCube loader, as well).
Side note: it is now under mpm_prefork instead of mpm_event. It could surely be done with any other, as well.
I do not have phpSwitcher plugin, so I have not tested phpSwitcher compatibility with a change to the base PHP, however, from the lines I saw that were holding up PHP 7.4, I don't believe it should be an issue.
If anyone cares, I can share the changes to imscp.conf, /var/www/imscp/engine/PerlLib/iMSCP/Requirements.pm, and /var/www/imscp/engine/PerlLib/Servers/httpd/apache_php_fpm/installer.pm
Not sure it's worth making a PR to github, as I'm sure there's more testing needed, and all of fluser's nice PRs are going ignored, so *shrug*