Channels? Congestion? Configuration? Maybe all three. You describe a number of issues, not all having the same cause.
I have a free app on my Android cell phone called 'WiFi Analyzer' which shows what WiFi channels are in use and by whom. Make sure you check the 5Ghz as well as 2.4Ghz bands. You may find that the dominant one is being used by your device that is having intermittent connection problems, and it is in use by another interfering one. Usually a suitable clear channel is selected by the router at time of bootup if it is allowed to select it in the configuration profile. If your neighbour has the same band as you in use, and the power outputs are similar, then you will have strong interference. Reboot your router and let it automagically select a more suitable band to transmit on as it boots up. The signal strength meter will be of immense help to identify shadowing and shielding by buildings and large metal areas, as well as confirm whether standing on one foot and facing Mecca may actually help. The app makes for significant understanding of how it all ties in together as the graphics and data is presented in a very concise and clear method. Well worth playing with for a few minutes, and keeping installed - a veritable Swiss knife troubleshooting aid I can't go without.
Another useful tool is called 'OpenSignal' which has the ability to do speed and performance tests. It also has a display of closest cell towers and indicates which ones you are connected to. Also free and useful in your problem solving toolkit.
Check which frequency bands your cell phone supports. Often a carrier will only offer a small range of bands that are common to both. The
https://www.phonearena.com/phones/compare website has a comprehensive database of most cell phones, and when you put your cell phone and that of your wife in the compare list, you can see what is common and what is not. Then check if your wife's cell phone has the same bands in the cellular and network sections. You may be connecting on a flimsy low power 3G signal and your wife on a 5G signal, as they are the only ones your carrier has available at that location that can be used by your respective devices. This may be eye opening when you confirm which of the bands and channels your carrier actually supports from the closest cell tower. Power off and on your cell phone and then attempt reconnection, as sometimes a cell phone will latch onto the first signal it can find and then remain on that one until it goes out of range, regardless of other more suitable ones.
If your neighbours WiFi signals are being boosted by larger antennas, illegal router transmitter settings or are overpowering, the temptation to use those signals instead of yours might be overwhelming. (If you can't beat them, join them - password cracking utilities exist if they are hesitant to proffer their password) This is not advice I recommend you take, just an option that may have fleetingly passed...
If you want to list the manufacturer and model numbers of all the devices in questions in your reply (both cell phones and routers), then we can probably offer more precise information. You will miss out on the fun however as you stumble about on the path of enlightenment.
Do us a favor. Please follow through on documenting your experience as you troubleshoot and what your final solutions are, as there may be others in the future that may benefit from your experience. Nothing more frustrating than seeing an unsolved problem forum thread go stale.