We want CTA to work even when email is forwarded from outlook.
Are you sure about that?
If you‘re using tracked Marketo links (the default) then if someone forwards the email, the recipient’s Clicked Email and subsequent Visit Web Page and Clicked Link activities will be credited to the original recipient.
This is almost never desirable, and if links aren’t clickable in a forwarded email, that‘s a good thing. Promoting the use of the Forward To Friend feature is better for all.
Now as for whether links in the original HTML show up after forwarding, this is something you can’t really control. There’s no standard way of (inline) forwarding an email. All mail clients do it differently and breaking the HTML structure should be expected. A text-only email of course doesn’t have this problem.