Hi

There are many online portals through which you can gain the required knowledge for free like Udemy, Coursera.

In Udemy, there are not any universities but you can search your instructor, if they provide in any course. Most of the courses are paid, but there are few courses for free and provide you Udemy certificate of completion. However, there are many time to time offers, which provides you up to 80% of discounts and is a great learning platform.

Coursera is the platform that fulfills your requirement of getting certified from top world universities. However, the courses are not at all free and you need to pay. But there are certain schemes like it provides "financial aid". There are also opportunities, like one that was given during Lockdown, with unlimited access to any course of top universities.

I suggest you to visit these websites from time to time to grab the opportunity.

For bonus, there is a platform called "Forage" which provides certifications for free from top companies for doing some tasks.

I hope you it covers your query.

Thank you!