I have thought mathematics online to primary, secondary, and tertiary school.

I have led training groups and individual trainings in the past for computer literacy, MS Office (Word, Excel, Powerpoint), basic programming for data science (VBA, SQL, C#, Python, Javascript). I have provided tuition for highschool students in mathematics and computer science.
I have completed software solutions development projects as a 'one-man-team' in distribution and logistics companies, delivering on business analysis, requirements gathering, solutions design, stakeholders' expectation management, software development (interfaces and back-end functionalities), debugging, user testing, implementation (deployment and training), post-implementation support and maintenance.
I am accustomed to preparing individual learning plans for learners, based on their chosen field of professional development. That includes training materials (examples to learn and exercises to practice what has been introduced).
In my experience, an effective format for studying programming in modular learning: starting with most fundamental concepts in programming, followed by more specific training, depending on choses area of development, and producing working code at each step to practice.
Programming languages can be of general purpose (creating fully functioning self-standing application for desktop or web-based platform), or focused on achieving subject specific tasks (such as data processing, analysis, game programming, etc.). Learning a language in programming is based on choice about where and what you would like to be able to do. The fundamental concepts, however, are not language specific and the knowledge is transferable. Think of it as, you can learn maths in English; then you can learn the words in Spanish and practice maths in Spanish, but that will not change the actual maths principles, only the means by which they are expressed.
There is no such thing as best programming language, but there is such a thing as a bad programming language. Granted, I do not know all of the good ones, but I can provide introduction of any modern programming language as part of the fundamentals programming module.