Android bug: E016: Request timed out

### Which version of floccus are you using?

5.26

### How many bookmarks do you have, roughly?

6k

### Are you using other means to sync bookmarks in parallel to floccus?

No

### Sync method

Nextcloud Bookmarks

### Which browser are you using? In case you are using the phone App, specify the Android or iOS version and device please.

LineageOS 20 (Android 13)

### Which version of Nextcloud Bookmarks are you using? (if relevant)

14.2.4

### Which version of Nextcloud? (if relevant)

28.0.8

### What kind of WebDAV server are you using? (if relevant)

_No response_

### Describe the Bug

When trying to sync, the app just hangs. The logs just have "Syncing failed with E016: Request timed out. Check your server configuration".

Complete debug logs

```
2024-07-14T07:09:00.592Z Starting sync process for account loveisgrief@nextcloud.internal
2024-07-14T07:09:00.609Z QUEUING POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:09:00.611Z FETCHING POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:09:02.064Z Receiving response for POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:09:02.208Z Using "default" strategy
2024-07-14T07:09:02.210Z Retrieving local tree
2024-07-14T07:09:02.232Z Retrieving server tree
2024-07-14T07:09:02.233Z QUEUING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/bookmark?page=1&limit=1
2024-07-14T07:09:02.233Z FETCHING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/bookmark?page=1&limit=1
2024-07-14T07:09:03.712Z Receiving response for GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/bookmark?page=1&limit=1
2024-07-14T07:09:03.714Z QUEUING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/folder/-1/hash
2024-07-14T07:09:03.714Z FETCHING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/folder/-1/hash
2024-07-14T07:09:03.849Z Receiving response for GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/folder/-1/hash
2024-07-14T07:09:03.850Z Filtering out unaccepted local bookmarks
2024-07-14T07:09:03.895Z Filtering out invalid server bookmarks
2024-07-14T07:09:03.895Z Filtering out duplicate bookmarks
2024-07-14T07:09:03.912Z Loading sparse tree as necessary
2024-07-14T07:09:05.772Z LOADCHILDREN + #-1[undefined] parentId: undefined, hash: 4858b415eb707cdd838a121773c65655b4444fe17d7a45541cbf2f25ab731346

2024-07-14T07:09:05.776Z QUEUING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/folder/-1/children?layers=1
2024-07-14T07:09:05.776Z FETCHING GET https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/folder/-1/children?layers=1
2024-07-14T07:11:02.067Z QUEUING POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:11:02.082Z FETCHING POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:11:02.406Z Receiving response for POST https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:12:05.796Z Syncing failed with E016: Request timed out. Check your server configuration
2024-07-14T07:12:05.810Z QUEUING DELETE https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:12:05.812Z FETCHING DELETE https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
2024-07-14T07:12:06.083Z Receiving response for DELETE https://nextcloud.internal/index.php/apps/bookmarks/public/rest/v2/lock
```

### Expected Behavior

Sync should terminate.

### To Reproduce

I might be specific to my bookmarks, but generate a bunch of bookmarks and they try to query them? I'm not sure. If there were logs of failed requests, I could be more specific. But I have no idea which request is failing. I tried calling every request listed in the logs, but they all succeed.

### Debug log provided

- [X] I have provided a debug log file

Start by tracing the sync sequence shown in the debug log, especially the GET request to /folder/-1/children?layers=1, which is followed by the timeout. Reproduce with a large bookmark collection and determine which request fails or hangs; done means the sync terminates and reports an actionable result.

Written by the indexing model from the issue text.