The requirements says I need to use Episrever CMS 11 to deploy to DXP (formerly known as DXC). I have talked to several people that claims web forms is not supported on DXP. Is this really true?
Can I deploy a web forms solution to DXP or do I have to rewrite to MVC first?
11.x will be the last version supports WebForm, so you should be able to run it on DXP https://world.episerver.com/blogs/Per-Bjurstrom/Archive/2018/10/cms-drops-support-for-webforms/
But as a long term investment I think you should move to some modern architecture for future proof.
The rewrite to MVC is part of the plan, but then it should be possible to move to DXP first, then rewrite to MVC later.