It's also recommended to use the Laragon Full version if you don't want to bother with this post.
If you download the laragon lite from the official site, it will give you the old php 5.6. So when you not ready to move to php 8 and want to stay a little longer with php 7.4 in laragon, here are the instruction.
You can go to https://windows.php.net/download and you can see the option to download the latest available PHP 7.4 version, I got PHP 7.4 (7.4.16) at the time, you can directly download it by this link https://windows.php.net/downloads/releases/php-7.4.16-Win32-vc15-x64.zip (the link may be dead, and you have to find the link of the latest version)
After it downloaded, you can create a folder inside
C:\laragon\bin\php (or your own custom directory) named after the downloaded zip file. The folder name for me is
php-7.4.16-Win32-VC15-x64 and then extract anything inside
php-7.4.16-Win32-vc15-x64.zip to this folder.
Try to right-click on Laragon desktop app, choose PHP, and click the
php-7.4.16-Win32-vc15-x64 option to change to this version.
Reload or restart the Laragon's apache server. When you hit the http://localhost on the browser, you should see this:
and by opening the Laragon's Cmder console and type
php --version, you should see this too
which indicates that the php 7.4 is properly installed.