Terrible Wifi speed when using two routers

Hi, im having trouble setting up a 2 router bridge-extender to get decent wifi in my office/shed in the garden

I have tried several configurations and cant really understand what the problem is.

Im always using two routers - one as a receiver of my home signal, the other as an emitter of wifi in the garden
.
The pair is connected via standard lan cable.and everything works, but the speeds are not good with certain configurations.

The one that works is:

Wifi ))))) [GL-AR300M-Ext/Shadow]-------(lan_cable)---------[TP-Link Archer C60] ))))) Laptop

No problems here, but i really want to retire the TP-Link Archer router as its old and makes annoying high pitched noise === 25mbps, 8ms ping average

Wifi ))))) [GL-AR300M-Ext/Shadow]-------(lan_cable)---------[GL-AR150/ White] ))))) Laptop
Wifi ))))) [GL-AR300M-Ext/Shadow]-------(lan_cable)---------[TP-Link TL-WR802N] ))))) Laptop

^when i use the small routers i achieve less then half of the network speed on either of those and also the ping is twice as high why ?
=== 7mbps, 16ms ping average

Tested multiple times one after another, i can always get the 25mbps on the big Archer c60, but never on any of the small routers (GL-AR 150 or TP-Link WR802N)
I got my laptop as close to them as possible and it doesn’t help.

I have been using the Archer C60 daily for a very long time now, all settings are default.
The networks are on different channels (Home network is on is ch1, output of tp/glinets is set to 6+10

Can anyone help me find out why this is like that ?

When you use repeater, the wifi speed cut 50%.

I suggest that you can upgrade your routers.
Your main router can be a more powerful GL-B1300 or GL-B2200
For your repeater router, you can consider dual band router e.g. GL-AR750.
Repeat wifi on 5G signal and you speed will be much higher.

Thats why i use 2 router system, to not have it cut.

Using 2.4G router as repeater, it may not provide good performance whatever.

So pls try dual band 5G wifi router.