PHP 7.3 upgrade says successful but stuck on 5.4

Question

I've been a PHP user for 20 years but haven't really managed installs/updates. For my current job (I'm the only developer), the server is PHP 5.4 and I got permission to upgrade to PHP 8.1, not sure how to accomplish it. Still learning my way around package managers too.

Using Yum, I see that the company has PHP 7.3 as the latest available. Rather than download the latest 8.1 from php.net and do all the manual configuring, I thought I would use yum, and I see this:

rh-php73-runtime.x86_64 : Package that handles rh-php73 Software Collection.
rh-php73-scldevel.x86_64 : Package shipping development files for rh-php73
rh-php73.x86_64 : Package that installs PHP 7.3
rh-php73-build.x86_64 : Package shipping basic build configuration
rh-php73-php.x86_64 : PHP scripting language for creating dynamic web sites
rh-php73-php-bcmath.x86_64 : A module for PHP applications for using the bcmath library
rh-php73-php-cli.x86_64 : Command-line interface for PHP
rh-php73-php-common.x86_64 : Common files for PHP
rh-php73-php-dba.x86_64 : A database abstraction layer module for PHP applications
rh-php73-php-dbg.x86_64 : The interactive PHP debugger
rh-php73-php-devel.x86_64 : Files needed for building PHP extensions
rh-php73-php-embedded.x86_64 : PHP library for embedding in applications
rh-php73-php-enchant.x86_64 : Enchant spelling extension for PHP applications
rh-php73-php-fpm.x86_64 : PHP FastCGI Process Manager
rh-php73-php-gd.x86_64 : A module for PHP applications for using the gd graphics library
rh-php73-php-gmp.x86_64 : A module for PHP applications for using the GNU MP library
rh-php73-php-intl.x86_64 : Internationalization extension for PHP applications
rh-php73-php-json.x86_64 : JavaScript Object Notation extension for PHP
rh-php73-php-ldap.x86_64 : A module for PHP applications that use LDAP
rh-php73-php-mbstring.x86_64 : A module for PHP applications which need multi-byte string handling
rh-php73-php-mysqlnd.x86_64 : A module for PHP applications that use MySQL databases
rh-php73-php-odbc.x86_64 : A module for PHP applications that use ODBC databases
rh-php73-php-opcache.x86_64 : The Zend OPcache
rh-php73-php-pdo.x86_64 : A database access abstraction module for PHP applications
rh-php73-php-pear.noarch : PHP Extension and Application Repository framework
rh-php73-php-pecl-apcu.x86_64 : APC User Cache
rh-php73-php-pecl-apcu-devel.x86_64 : APCu developer files (header)
rh-php73-php-pecl-xdebug.x86_64 : PECL package for debugging PHP scripts
rh-php73-php-pgsql.x86_64 : A PostgreSQL database module for PHP
rh-php73-php-process.x86_64 : Modules for PHP script using system process interfaces
rh-php73-php-pspell.x86_64 : A module for PHP applications for using pspell interfaces
rh-php73-php-recode.x86_64 : A module for PHP applications for using the recode library
rh-php73-php-snmp.x86_64 : A module for PHP applications that query SNMP-managed devices
rh-php73-php-soap.x86_64 : A module for PHP applications that use the SOAP protocol
rh-php73-php-xml.x86_64 : A module for PHP applications which use XML
rh-php73-php-xmlrpc.x86_64 : A module for PHP applications which use the XML-RPC protocol
rh-php73-php-zip.x86_64 : ZIP archive management extension for PHP

I've installed rh-php73.x86_64 and rh-php73-runtime.x86_64, also rh-php73*, and it always tells me it was successful, but when I check the php version, it's still php 5.4. I've restarted Apache and the whole server, no effect.

I can't figure out where it actually installed the files. I have no idea how Apache knows where php is, I've looked around at the php.ini file and various httpd.conf and related files. I'm on Centos 7. Any help is greatly appreciated.