When a web project goes badly, the expensive part is rarely the design or the code. It is discovering that the domain sits in a supplier account, the ad history belongs to someone else, and nobody can hand over the source because it was never arranged.
None of this needs mistrust to go wrong. It goes wrong through defaults: whoever set it up used their own account because it was faster, and nobody wrote anything down.
Domain and server
The domain should be registered to the company, on a company email address that outlives any individual. Renewal notices should reach someone who reads them. A lapsed domain is recoverable at a price and sometimes not at all.
The server can be managed by whoever runs the site, but you should either own the account or have regular backups you can actually restore from. A backup nobody has tested is not a backup.
Accounts and code
Analytics and advertising accounts should be created under your company with the agency added as a manager. Done the other way round, the history that makes future campaigns cheaper leaves the moment the relationship does.
Source code should be delivered, in a repository in your name, with enough documentation that another team could pick it up. Ask for that at the start; asked at the end it becomes a favour, and favours are negotiable.
A structure set up correctly changes nothing while the relationship works, and everything if it stops.
What the contract should say
Four lines cover most of it. The domain and hosting accounts are registered to the company. Analytics and ad accounts are owned by the company. Source code and its documentation transfer on final payment. No licence is retained over delivered work.
None of these are unusual requests and none should cause friction. If they do, that reaction is itself information.
What to do now
Check four things this week. Who is the registrant on your domain. Who owns your analytics property. Who owns your ad account. Where the source code lives. If any answer is a supplier name, fix it while everyone is still friendly.
If you inherited a setup and are not sure what you actually control, we can go through it with you and tell you plainly where you stand.