ASUS - RT-AX68U

Buy used, get a AX68U or something similar for under $100. Use the rest of the money for NAS or switches.

The ASUS RT-AX68U is a pretty solid, moderately-priced ASUS router. If you're considering other brands and just want a basic, reliable router, the TP-Link Archer AX20 is good option, too.

I've had zero problems with M1 for many years. Only went down once, and that was for scheduled maintenance in the middle of the night. Also, it's not just your internet plan that could be the cause of any issues. If your router isn't good enough, or is in a terrible position, or is overheating, or the bomb shelter is between your laptop and the router, you are gonna have issues no matter what plan you have. I have a standard 1Gbps plan but an Asus gaming router with ethernet cables going to the 3 heaviest users in the home – PS5, living TV and bedroom TV. I also set up a second router using Asus AImesh to provide wifi signal to one of the further corners of the house.

I've been using AiMesh since the beginning, and it was rocky at first, but now I'm currently quite happy with it. One solid main router and two APs outside. What unifi did you get to replace your setup and do you think it was worth the cost?

Asus AiMesh - Yea TP-Link Deco - Yes TP-Link Easy Mesh - Not sure

I use Asus routers in my Ai mesh network and it gives me complete control over everything and I've loved it. I use that coupled with family link from Google and I feel like I've done my job as a parent blocking as much bullshit as I can for my kids.  But don't worry, their friends who's parents don't care about a single thing they consume will come along and ruin your hard work. Or your kids will be kids and find loop holes, which they always do. But you still tried. 

Asus AiMesh can be configured without an app and uses local credentials for management.

I went from DD-WRT for years to ASUS AiMesh and have been on Unifi equipment for a good four years now. I never have any issues with roaming (3600+ home) and I can fine tune whenever necessary (rare). I love the Unifi and don't plan on moving away any time soon. If you want peace of mind, I definitely also recommend Unifi.

As has been said, plug in everything you can. For a basic option, the Asus routers with AiMesh are a pretty simple solution. Start with one on the second floor centrally located and see if you need more. Use inSSIDer to see how your signal strength is as what kind of interference you have and set settings accordingly. If you’re not reaching all corners, add another compatible Asus and put them on floors 1 and 3 (both wired connection to WAN jack)

Avoid tp-link and any other CCP networking equipment. Don't intentionally put stuff with backdoors in them just to save a few bucks. Unifi is great but it's expensive and you really should use it wired. If you're just looking for plug and play mesh Asus has good offerings. Their AI mesh system works well