[Bug]: Large upload fills RAM until DOS, No Upload happens.

### ⚠️ 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

Uploading a few thousand small files with the 3.15 client on linux(Manjaro) causes the client to freeze. While frozen, in the background, the app is still running and uses up all available memory(16gb) until full system DOS, the only way to recover the system is with a hard reset risking data loss and disk corruption. No actual uploading even starts.

I see in past issues bulk uploads have generally only led to client crashes or slowdowns, however this bug is crashing the entire system running the client.

I have not tried this on a fresh system in vm and i do not know if it was present on recent previous versions. Can anyone else confirm large uploads causing their systems to crash like this?

### Steps to reproduce

1. Have a folder to upload. (im trying my Steam compatdata folder since Steams own cloud system sucks, 20gb)
2. Add a new sync connection in the NC client to that folder.
3. Cry.

### Expected behavior

1. Have a folder to upload. (im trying my Steam compatdata folder since Steams own cloud system sucks, 20gb)
2. Add a new sync connection in the NC client to that folder.
3. Files from folder get uploaded, and i dont lose any more saves to steams cloud nonsense.

### Which files are affected by this bug

~/.local/share/steam/steamapps/compatdata

### Operating system

Linux

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

Manjaro

### Package

Distro package manager

### Nextcloud Server version

30.0.2 (AIO v10.0)

### Nextcloud Desktop Client version

3.15 and 3.15.2

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

Updated to a major version (ex. 3.3.6 to 3.4.0)

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

Encryption is Disabled

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

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

### Nextcloud Server logs

```shell

```

### Additional info

_No response_

No source files or tests are named. Start by reproducing the sync with ~/.local/share/steam/steamapps/compatdata using Desktop Client 3.15.2 on Linux, then trace memory use during the upload; done means large folders upload without exhausting system RAM or freezing the client.

Written by the indexing model from the issue text.