Currently the useDomainSearch() and useTitle() hooks get/set the site title by accessing core functions. In particular:
The new hooks introduced in https://github.com/Automattic/wp-calypso/pull/46881 should be used instead.
Reopening as there are still changes to be made in packages/launch/src/hooks/use-domain-search.ts
there are still changes to be made in packages/launch/src/hooks/use-domain-search.ts
Fixed at https://github.com/Automattic/wp-calypso/pull/47141/files#diff-fd3904ca53e493ed641e3deffd5efb5fd5a320c2aa489342a0c820f6dc573044