There are well-known universities, companies, and non-profit organizations that have made large efforts to make large amounts of university-level educational content available for free.
Examples include MIT OpenCourseWare and Khan Academy. There are undoubtedly many others you can find with a google search.
That means that it should not be difficult to find free and reasonably high quality content for most mainstream undergraduate education topics. For more specialized topics it will be more hit or miss. For some topics you may get lucky and find good content some professor was kind enough to make available, for others you won’t.
The main problem has to do with your first question:
Is following a curriculum from a university a good way to achieve my goals?
Well, we don’t know what your goals are exactly. If your goals are getting a university degree, one big problem is getting someone to certify the knowledge you’re acquiring via tests and other assessments, and eventually award you a diploma. That’s usually not free.
And another big problem is that even if you just want the university education rather than a degree, most people don’t have the discipline and other skills required to study all the material for a college degree on their own even if it is available. A true university education consists of more than a one-way consumption of knowledge (even very high quality knowledge), but rather is a two-way interaction in which you go to a campus, sit in lectures, ask questions, talk to your peers, and do many other things that involve interacting with your fellow students and with the teaching faculty, all of which facilitate the learning process. A university is like a very large positive feedback loop in which thousands of students and professors all reinforce each other’s motivation and intellectual progress. By consuming all the material online on free education platforms, you will miss out on this very significant aspect of what a university education is about.
That being said, the education platforms are used by millions of people who find them beneficial. They’re quite good in lots of ways, and certainly are infinitely better than getting no education at all. And some people - I would say a very small fraction of people - are autodidacts who truly have the ability to learn difficult material entirely on their own with no feedback from others. Those rare individuals can probably get as much benefit from studying free online content as from attending university in person.