Instead of having to start from scratch and take weeks trying to figure out why our codes don't work. Frameworks provide quick solutions to our problems. Frameworks are libraries of preconfigured code that usually follow some standard. It can be used in your projects to save you time or make coding easier and offers better performance. Instead of typing 30 lines of code or more. You only need to type 1.
Frameworks save time and provide recognizable structure but can often add unneeded weight to small apps.
This should answer a lot of your questions: https://hyperskill.org/learn/step/6701
Yes... Framework maybe save Time, help with best practices, security (in certains) but its very important know about base language... So you can work with efficiency when some things go wrong☺️