[Bug]: Nextcloud client deletes everything on server

### ⚠️ Before submitting, please verify the following: ⚠️

- [x] This is a **bug**, not a question or a configuration issue.
- [x] This issue is **not** already reported on Github (I've searched it).
- [x] Nextcloud Server and Desktop Client are **up to date**. See [Server Maintenance and Release Schedule](https://github.com/nextcloud/server/wiki/Maintenance-and-Release-Schedule) and [Desktop Releases](https://nextcloud.com/install/#install-clients) for supported versions.
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/)

### Bug description

I host Nextcloud on TrueNas Scale and used it locally. So the host was a local IP (192.168...). I got to make the server accessible remotely under a custom domain to reach it outside my local network.

When I wanted to switch accounts from the local host to remote host with the same account, I got some problems and the client deleted all my files on the server by "syncing". I use Windows and proxied all the files either on the local and remote hosted accounts.

As suggested in [this issue comment](https://github.com/nextcloud/desktop/issues/1433#issuecomment-2323725545), I am opening a new issue for my specific problem.

### Steps to reproduce

1. Create a new dummy account with default files.
2. Add a few files into subfolders, like `Documents/School/HomeWork.md`
3. Login to Client with local host account.
4. Choose proxied files.
5. Add remote host account.
6. Choose proxied files with same sync directory as the local host account.
7. Remove local account (files should remain intact). (might be an optional step to avoid conflicts)
8. Remote account should sync everything in the directory of the local synced account.
As files are proxied, they are not found in the folder and considered as deleted by remote account's perspective. So the remote hosted account deletes the not locally found files in the nextcloud server.

### Expected behavior

When the remote account syncs, it does not delete locally not found files on the server.

### Which files are affected by this bug

Documents/School/HomeWork.md

### Operating system

Windows

### Which version of the operating system you are running.

Windows 11 IoT Enterprise LTSC 26100.2161

### Package

Official Windows MSI

### Nextcloud Server version

30.0.1

### Nextcloud Desktop Client version

3.14.2

### Is this bug present after an update or on a fresh install?

Fresh desktop client install

### Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

### Are you using an external user-backend?

- [x] Default internal user-backend
- [ ] LDAP/ Active Directory
- [ ] SSO - SAML
- [ ] Other

### Nextcloud Server logs

_No response_

### Additional info

_No response_