Issues with my network speed

I have AT&T fiber with a 100 Mbps plan, which is perfectly fine—I get the full speed when I test via an Ethernet connection. However, things went sideways when I decided to move my desk from my bedroom to the living room (mostly because the AC is located there 😬). Typical of how service providers operate here, they didn't bother installing a proper wall jack or anything useful; instead, they just ran the fiber line straight from the hallway into the room, plugging it directly into the ONT sitting on my desk. Now, my laptop is barely pulling 10 Mbps over Wi-Fi in the living room! My router is a Netgear router, and my laptop uses an Intel AC 7260 card, which supports 802.11ac and claims max speeds of 300/867 Mbps.

I managed to fish the Ethernet cable connecting the ONT and the router through a hole in the wall to get the Netgear router into the living room. It’s now about a meter and a half away from my laptop in a direct line of sight, yet the speed barely hits 30 Mbps. Honestly, what gives? I've heard people say the Netgear router is garbage when it comes to Wi-Fi (which makes sense given it lacks external antennas), but is it really this bad? Is there some setting I should tweak? I haven't touched anything since the AT&T technicians set it up. Is the issue definitely the Netgear router, and if so, should I complain to AT&T and demand a better model that can actually deliver the speeds I'm paying for within the same room?

The second option is to move the router or at least run a cable back to my desk, but the Ethernet cable required would be far too long and unsightly, making it difficult to pull off. My thought was to extend the fiber line itself and bring the ONT right to the desk. Fiber is thin and translucent, almost invisible, so I could easily route it around the apartment. The problem is that buying fiber by the foot and then attempting "installation" with connectors seems impossible for us laypeople without incredibly expensive equipment. Furthermore, I can't even find pre-made extension cables with a female connector on one end and a male on the other to simply lengthen the existing line. Where does one even buy such things? This would also solve another headache: the current setup is frankly idiotic. The ONT actually fell off my desk while I was cleaning once, breaking the cable and forcing them to rerun everything from the hallway all over again. Given how clumsy I am, that's likely to happen annually. It's just foolish that they didn't install a wall jack; if they had, I could just swap out a short patch cable myself whenever it breaks rather than waiting a week for a technician to show up.

The third option is using a Powerline adapter, but those are just too expensive.

My Wi-Fi is acting up sometimes—even after the folks at Xfinity swore I was getting over 10 Mbps, my wireless speeds were hovering around 5 right next to the router. Meanwhile, if I plug in via Ethernet, I’m pulling nearly 11. Honestly, nothing beats a hardwired connection.

I was reading somewhere recently that they only started issuing the Netgear routers with the AC standard lately. I’ve had mine since last December, so there’s a decent chance I’m stuck with an older version. I'm not at my place right now to check the specific model number on the unit itself, but if that's actually the root of the issue, then the technicians better step up and fix it properly—or just bring me a new one. Look, I know nothing beats a hardwired connection, but if I can pull 100 Mbps over Wi-Fi (which, if it's actually AC standard, it absolutely should be able to do), I really don't want to deal with the headache of running cables through the house. I saw someone else on another forum bragging about hitting over 200 Mbps from just 13 feet away.

That leaves me wondering: is it even possible to buy an optical extension? If I end up giving in and going the wired route, I might as well run the fiber straight to my desk.