Really slow transfer and indexing speeds

New to urBackup :).

I installed it on a local server here at the office running Debian 11. New machine, nothing else on it.
NVMe disks so I have really good read/write speeds.
256 Gb of ram.
Latest version of the server 2.5.26.
Using the latest version of the client: 2.5.20
Installed it with BTRFS.
Client is running on a Windows 10 21H2 (Internet connection, not local).
NVMe disks with really good speeds.

iperf shows transfer speeds of ~50Mbit/s between client and server.
Transfer speeds with urbackup never exceed 100kbit/s.
Indexing just 10 files takes almost half a minute.
Transferring a 33Mb file takes ~40 minutes.

Tested to change all transfers to RAW, tested with and without both encryption and compression but no change from the 100kbit/s is shown.
Reinstalled the server with ext4 on the storage drive instead but still have the same issue.

Just to mess around with it I also installed a server at Contabo in Germany to see if there is any difference but I still get the ~100kbit/s ceiling.
Tested Ubuntu instead of Debian, same issue.

Changed to another client (my own laptop) and I get the same issue wether I’m connected through wifi or ethernet.
Was working at one of my customers earlier today and tested it with their internet connection, same issue.

I’m actually a bit stuck now… Is there anybody out there with an idea of what could be wrong?

I have no antivirus activated and I have also tested to deactivate the “run service in background” but still, nothing that solves the indexing or transfer issues.

I made a mistake. Client is a Windows 11 21H2, not Windows 10.

@skotty Try the old 2.4.x client. Works for me…