Torrent speed changes rapidly

[Chandler6000]

Hi,

I have a problem with speed, since it changes rapidly from 100kbit/s to 3Mbit/s and back.

I use NAS as a storage for files. My internet speed is 1000Mbits/100Mbits.

I use proxy settings (Torguard) and port forwarding on my router.

What can I do to fix this?

Please ask any questions and I will answer them.

TIA

[Chandler6000]

Update:

I re-installed QBittorent.
My download and upload speed according to speedtest are 950Mbit/s IN, 95Mbit/s OUT

It seems that the speed is constant now.

I have default settings, VPN proxy and router port forwarding.
I use NAS (Seagate Ironwolf, cache 64MB) via 1Gbit ethernet.
Best settings that I have tested are 100 connections per torrent, 2 simultaneous downloads and no restrictions on speed (out or in).
The best I can get is 15MB/s IN total.

Is there a way to boost the speed somehow?