Thanks for all your replies guys!
Here is some details about my current device:
Product name: Business Smart Hub
Firmware version: SG4B1B008146
Firmware updated: 28-Apr-2018
Board version: 1.0
Gui version: 1.91.5
DSL uptime: 0 Days, 8 Hours 9 Minutes 16 Seconds
Data rate: 1.26 Mbps / 21.32 Mbps
Maximum data rate: 1264 / 21384
Noise margin: 6.2 dB / 6 dB
Line attenuation: 6.6 dB / 13.5 dB
Signal attenuation: 6.6 dB / 13.5 dB
VPI / VCI: 0/38 - 0/35
Modulation: G_992_5_ANNEX_A
Latency type: Fast Path
Data sent / received: 229 MB Uploaded / 241 MB Downloaded
Do noise numbers looks good?
Connection information:
Connection time: 0 Days, 8 Hours 13 Mins 48 Secs
Data usage: 239 MB Uploaded / 246 MB Downloaded
It's really not heavy.
To reassure some of you, all WiFi devices are smart sockets with WiFi functionality, which enable me to watch power usage, switch on and off sockets remotely from my phone. All remaining Ethernet devices are miners.
There is one Linux server there, so I could try to make a bridge. This is very interesting and promising idea! I am just hoping I will be able to do that on Linux!