How can I bypass website's download limits?

It depends on how they're blocking you. Personally, I'd just let it run through whatever limit until all the files are downloaded.

There are also lists one can find of open proxy servers, they're all probably malicious but if just getting a single file via https... it would be non-incidental to override the certificate check, so these gutter proxy sharks are probably not at that level unless a major state actor wants you.