This is surprisingly simple if you don’t want to mess around with multiple versions and just switch to 7.4. Run as root:
# dnf -y module reset php
# dnf -y module install php:7.4
Then in my installation a few pecl modules needed to be reinstalled (zip needs the extra step below):
# pecl uninstall imagick && pecl install imagick
# pecl uninstall mcrypt && pecl install mcrypt
# dnf -y install libzip libzip-devel
# pecl uninstall zip && pecl install zip
And finally restart the web server:
# systemctl restart httpd php-fpm