The unsubscribe and profile center links (standard marketing cloud ones, no customization) at the bottom of my emails are currently showing up as unsecured when clicked. Setting up SSL with marketing cloud is being quoted at 4-6 weeks which seems very excessive. Is there any way to expedite this or get a workaround where I can have those links link to a secure trusted landing page so they work.
As already mentioned in your other question.. It's not mandatory but it's the only way to go if you've purchased SAP. When you place the order, you should get two SSL certificates in total, for:
Securing microsite, landing page, or CloudPage URLs which would typically use your existing Sender Authenticated domain (e.g. pages.SAPdomain.com, cloud.SAPdomain.com, or pub.SAPdomain.com). With this option we can also secure view. and click. URLs for links within your SFMC content.
Securing portfolio content URLs, which use your existing Sender Authenticated domain (e.g. image.SAPdomain.com).
The second one has become even more important lately with Chrome Blocking Mixed Content.
There is no other way around it and it's not possible to speed it up - even if you get the SSL yourself, you will end up waiting ~4 weeks to have it activated in your account.