ZTE - ZXHN H268A AC1600 VDSL/ADSL NBN Modem Router

I've recently upgraded my Exetel plan to the 500/50 but am in an old terrace in inner north Melbourne and despite having a tiny 2 bedroom place, the internet at the front of the house is crap, very weak wifi signal. Unfortunately my NBN connection is at the far end of the house near a TV. I moved the router to sit on the floor instead of behind the TV where it might have been causing issues, but that hasn't solve the problem. I have a shitty old ZTE router from 2019 that I need to replace, as I assume apart from upgrading technology, I need one compatible with a mesh extender. Exetel recommend the ZTE 1600 but I cannot find a retailer to sell it to me and I'm bloody confused what to buy. I checked what Superloop recommend, but the eero 7 looks so expensive, especially if I have to buy an extender! The house is tiny, so surely I'd only need one, but these come in packs of three. \[Edit: I'm not fully cash strapped, willing to spend right amount of money, but am totally confused to how much that should be. Is $350 reasonable??\] NBN is HFC if that makes any difference. I use the internet for work, TV streaming, but no gaming etc. 1 - 2 people max. Grateful for any recommendations of suitable technology for the house. Ideally a combined router/modem and 1 extra node to extend the wifi coverage in the house. . Oh - one more thing: The unit is in the living room, so bonus if it's not hideous and looks sleek, small.

It's a ZTE H268A and exetel have told me it's not compatible with extenders.