Several months going through an interview is too much. No company is worth that much time unless you have an attorney drawing up contracts along the way, so that is the first red flag.

Now, the hiring manager convinced you to spend evenings/weekends prepping for coding and design interviews. This sounds training, and by law they may have been required to pay for that. In the future, you shouldn't spend more than an hour or two prepping for an interview unless they offer to pay. If you don't have the skills needed, then I'd recommend just telling them that. Companies that try to get you do make a big initial unpaid investment in time will also be the kind that will expect you to work a ton of overtime unpaid.

In regards to the remote work, get it in writing upfront. Recruiters are dirty, so maybe this is a valuable lesson to understand that from now on.