The published interface
Linq markets a developer API, CLI and sandbox across iMessage, RCS, SMS and voice. The advantage worth investigating is the ability to connect several communication paths without maintaining unrelated vendor integrations for every one.
The quote you need
No numeric production rate was confirmed on the public pages used here. Supply your intended line count, new contacts, recurring traffic and voice needs when asking for terms. A quote for another team or an older competitor article is not a reliable substitute.
Adapter design questions
Before implementation, request examples of inbound events, delivery updates and channel changes. Determine whether a reaction, attachment or participant identifier needs different handling across channels. Keep vendor-specific semantics inside a small integration boundary so the rest of the application can reason clearly about outcomes. That is a design recommendation, not a claim that we have deployed Linq in production.