Nexctcloud client 34.0.2 not syncing

### ⚠️ 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 have searched for 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

@camilasan This is the new bug report, originating in https://github.com/nextcloud/desktop/issues/10513

Version `34.0.2` of the Nextcloud Client for Windows is still not working for me - upgraded from `33.0.7` and many versions before.

* I created a local file `nextcloud-test-sync\nextcloud-upload-test-sync.odt` which never gets uploaded to the server.
* I created a file `nextcloud-download-test-sync.md` (the folder `nextcloud-test-sync` from before also doesn't get "uploaded") on the server. It never gets downloaded to the client.

Switched back to `33.0.7` and both directions synced immediately.

I have a **Nextcloud debug archive** of the actions, but i found not a single mention of the files created in the `20260820_0710_nextcloud.log.0`.

In regard to https://github.com/nextcloud/desktop/issues/10513#issuecomment-5352069956
> Have you tried to temporarily disable the windows defender realtime scanning? Pause the nextcloud sync, disable the scanning, start the sync and wait a bit. Not a solution but a workaround for the time being.

That seemed to work. And it seems like it survives a restart of the Nextcloud client. But i am not sure, is this a lasting solution on my Windows laptop? And it's certainly not a solution for other managed Windows clients, therefore i am keeping those clients on `33.0.7` for the moment.

### Steps to reproduce

* I created a local file `nextcloud-test-sync\nextcloud-upload-test-sync.odt` which never gets uploaded to the server.
* I created a file `nextcloud-download-test-sync.md` (the folder `nextcloud-test-sync` from before also doesn't get "uploaded") on the server. It never gets downloaded to the client.

### Expected behavior

Files should sync

### Which files are affected by this bug

multiple files on client and server

### Operating system

Windows

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

Windows 11 Pro 25H2 (26200.9168)

### Installation method

Official Windows MSI

### Nextcloud Server version

34.0.3

### Nextcloud Desktop Client version

34.0.2

### Did this occur after an update or on a clean installation?

Major version update (i.e. 4.0.0 → 33.0.0)

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

No

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

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

### Nextcloud Server logs

```shell

```

### Additional info

_No response_