https://lawcomic.net/ — goes into digressions about english common law and also the history thereof.
A warning on this topic: it is easy to fall into the trap of thinking you know more than you really do.
You don’t have to learn law because that means reading up laws you might not necessarily be interested in or have any practical uses for. Learning formal logic should suffice, then really read anything that you are signing.
Not a course, but a good resource for finding up-to-date versions of laws in the US.
You could listen to “Law School for Everyone”, a lecture series from The Great Courses. It is supposed to broadly cover what a first year law curriculum would.
I found it interesting.
I’d read cases in your states court site and the decisions given by judges. Research terminology and process via the Cornell law site.
I went back to university to study law part-time (night school along with lots of ex-police, PIs, etc). Although I dropped out, I gained a basic understanding by following the law school's curriculum. The most valuable thing I learnt was that even if I had completed the course and got admitted to the bar, I would have only ended up on the first rung of the ladder to being accomplished in whatever area of law I chose to specialize in.
If large sums of money and/or potential professional liabilities are involved, then cheapest long-term approach is to hire a competent licensed lawyer.