Bought an established home (just moved in) that is FTTP with one ethernet port connected to the NTD. The position of the ethernet port is a wall away from the garage at the front of the house. Our offices are at the back, passing through at least 5 walls plus cupboards to reach the modem. We are currently using an old iinet 2017 Technicolor modem. I bought and tried a TP Link ARCHER AX10 AX1500 but it turned out to be worse which was very surprising.
In this situation would a higher AX, say AX5400 provide a strong enough signal to the back?
I have read mixed reviews about mesh systems mainly that they're amplifying an already weak signal so a bit unsure on that.
There are no other ports to run another router in the house.
Back at my parents my dad just drilled a hole in the roof and wired the ethernet through but I'd like this setup to be neat.
No idea about the mesh system but you could try a wifi powerline adapter. Instead of using a wired ethernet cable for connection, it uses your ac sockets to create an internet connection.
They come in sets of 2. One goes in the ac socket near your original ethernet connection front of house and you plug it into your router there. The other you plug it in at the back of the house and it'll give you an ethernet port out - you can then ethernet cable directly to your computer or to a router to make the wifi signal from there.
I had a similar situation to yours and this solution worked surprisingly well (had dropouts, lag on some online games). It was pretty cheap to try too (~$15 for a set of used foxtel powerline adapters from eBay). Plugged them in at either end and it pretty much started working like you'd expect.