I dropped $78 on an extender that didn't work.
Im wondering if I get a stronger router.
Stronger isn't necessarily better. You typically want your wireless access point configured at lower power outputs (people set theirs on 100% or max thinking that is he best, but it isn't).
If you're trying to get more coverage in your household, I'd recommend either relocating your current WAP somewhere central and elevated in your house or adding another WAP in the house. You can certainly broadcast the same SSID from both WAPs - most devices are intelligent enough to choose the SSID with the better signal.
If you don't have an existing wire, like I keep mentioning, try a powerline device. It will extend your physical network via your electrical wiring (you plug one on one outlet near your router/switch and the other where you want to extend your physical network to).
I don't know a ton about wireless mesh (I get the concept and the application), other than that it's all the rage in the consumer market right now (which is why they are ridiculously expensive). But I think most are better served running two autonomous WAPs with the same SSIDs and authentication configurations. There are some WAPs that implement mesh-like protocols without the cost.
Though, if you have cash to burn, I'm sure those newly marketed WAPs will be pretty cool, are probably very easy to setup, and will run wonderfully. One great thing about them is that you get multiple WAPs with easy integration of additional ones in your house, which is good as 5g signals don't travel very far, so most folks don't get the full benefit of 5g on dual-band devices. So if you do get one of the newer WAPs, make sure to place one near applications that could benefit from running at 5g (like streaming devices - Apple TV, Chromecast, etc).
