We have used 'Launch Command' and have been able to switch Launch header code from one Akamai header(Adapter) to another Akamai header(Adapter).
But is it possible to use Launch command and switch from Akamai to Self-hosting path and vice versa ?
Yes, Launch Command will detect any libraries on the page deployed by DTM or Launch whether those deployments use self-hosting or are hosted by Adobe using Akamai.
And you can replace it with anything you paste into the Launch Command settings, so that can be self-hosted or Akamai-hosted (or anything else you'd like).
Keep in mind it only impacts the current browser you're using, so the changes are only taking place for you. The use case is around testing.