what exactly is composer and monolog

Can I add my own written libraries?

Yup composer supports 3rd party libraries including your own.

If you hate them, you might not be ready to use them in my honest opinion.

Frameworks and Libraries shouldn't make programming in any language more difficult. They exist to improve workload and simplify common time consuming problems.

For example I wouldn't expect anyone to jump into a PHP framework before they have a good understanding of both procedural PHP and Object Oriented PHP.

Mohammad if you looking to make a career out software dev then I suggest you specialize in a language and a framework, maybe a few frameworks. Most companies are looking to fill gaps in their teams specialties. For example a dev team may be really focused on PHP and may not be amazing at javascript, so they might be looking to hire a javascript developer. That doesn't mean you wont know some other languages but I would really focus on something you enjoy doing. It is ok if you do not know everything the job ad requires. As long as you show you have worked with something similar and are willing to learn then you will be fine! Keep up the hard work!

Also bear in mind that 90% of job ads ask for more then the minumum they expect. I refer to these as unicorn roles.. because the person they are looking for is either incredibly rare or non existent. But if you fall into atleast 40%-50% of the roles requirements you will normally find that employers will be bit more relaxed on their requirements when you do go to the interview, most employers do not expect to find someone that ticks every single box of the job requirement.

I would pick a language and specalize in it, then look through job listings and find the frameworks that are most commonly advertised in your area and focus on one (If you build enough knowledge in the core programming language, most frameworks are quite easy to understand even if you haven't learnt everything about them)

I am a Fullstack Developer but I have specalized in PHP.. the most popular frameworks for PHP are laravel and symfony in the job market. But I specalised in Zend Framework 2, because looking through my local jobs (London) the majority were looking for Zend Framework 2 experience. (It difers by location which framework is popular, but looking at job adverts you can narrow down the most required).

Also take into account of rarity as well. For example if I do a job search for PHP roles in London I will probably find about 8000 jobs.. but on that same job site there are 140,000 PHP developers looking for jobs. Then if I search for Python roles there is probably about 300-400 roles. But only 1500 Python developers to compete with on the website. This influenced me into picking Python as my second backend language, there is less jobs but less competition.

On a side note I switched from Network Sys Admin to Programmer and found there was far more things to stay up to date with and contantly learn being a Network Sys Admin.. and you get paid 1/4 of the wages as a Sys admin (Atleast here in London you do, and in London its near impossible to land a job with the other 100,000 sys admins applying to the same role.. its a bloated sector.. I was made redundant as a Project Leader/Sys admin from one of the largest prestigious hedge fund administrators in the world.. and struggled to walk into another Sys admin job even with that experience on my CV).