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.