For the record:

 

1.2.1 Build 20200110 rel.60118(4555)

Archer A6 v2.0

 

1.0.1 Build 20191206 Rel. 56929

TL-WA850RE v6.0

 

Now first of all, sorry for my bad english but i'm desperate.

 

I'm from Romania and my ISP is RCS&RDS, i have a 300MB connection via some device (i think is a modem, i will put a link to a pic of it) from Huawei that ISP gave to me.

 

Here is that pic: https://imgur.com/5KmV0Y2

 

I run several test like speed test and ping test and on direct cable from moden is perfect speed, after that on cable connected on my router is also perfect BUT...

 

On my Archer A6 on 2.4G is unstable internet connection with high ping, it dosen't matter if i'm connected on router or on my range extender.

I disabled 5G ac network, i have 2 laptops  and 2 android smartpones which I tested and the result is the same. My connection type is PPPoE. I'm alone on chanel number 7.

 

IGMP Proxy is Enable and IGMP Version is V2, IPTV/VLAN is Disable

 

IGMP Snooping is Disable

 

DHCP Server is Enable

 

Dynamic DNS is set on TP-LINK i have other 2 option NO-IP and DynDNS but i think is Disable because i check on my ISP account and is off and under my router settings it says ''DDNS Unavariable''

 

IPv6 is Disable

 

At Network setings is show me IPv4 and when i click Advance setings is show me Secondary Connection is check on ''None''

 

IP Address: Get dynamically from ISP

 

DNS Adress: Get dynamically from ISP

 

Connection Mode: is set on Auto

 

SPI Firewall is ON

 

DoS Protection is OFF

 

Thanks for help in advice guys :D