For the shop that's already in it
Stop absorbing it. Start recovering.
The enterprise is making you feel like you owe them. Your SOW is vague enough that everything seems like your problem. Their team is contacting your devs directly, pulling them into meetings that were never in scope. Someone on your team is burning out. You've blown past your quoted hours and you're losing money on a job you needed to put on the map.
You don't need advice. You need someone to step in.
David steps in as your liaison. Between your team and theirs. Between your developer and their meetings. Between your contract and their scope creep.
The first step is understanding exactly where the engagement is, what's been absorbed without being paid for, and what's recoverable. From there it's about stabilising the relationship, drawing the line on unscoped work, and making sure your developer can get back to building.
Project-based. Scoped at first conversation.