Which torrent client to choose?

Question

linux

There is such a task to keep (ratio: 1:1) a large number of torrents. Approximately 600-700.
Some can download, some can stand due to the lack of seeds. But all should hang
For a long time there was a transmission daemon. He suited us just fine.
Now I discovered that at 400 torrents it starts to shamelessly slow down. RPC and GUI don't respond well.
Now I am considering any other clients that:
1. Work under ubuntu server as a daemon (by the way, this is not critical. We have allocated a separate unit for this, so we can install any other OS)
2. Can hold 500 or more torrents
3. RPC or any method of remote software controls: adding, deleting, information about torrents
4. And the obligatory ability to move to another folder after downloading
Please tell me who knows what. Looked through the options, but can't find information about the number of concurrent torrents.
I didn’t pick up any configs for transmissions - all the same, brakes with a large number are guaranteed

Answer 1

And you do not want to run 2 demons, dividing the torrents between them?

Answer 2

Very good combination of rtorrent + WebGUI rutorrent

Answer 3

I just know that points 1, 3 and 4 are performed by Deluge .

Answer 4

I have uTorrent for linux about that much.

Answer 5

aria2c