1. Yes, perform a full reset to factory defaults on the nodes. Do not connect to them directly via their GUI. Use the add AiMesh node function in the main router's GUI to re-associate them.
2. Performing a proper/full reset of the router's firmware does not revert it to stock firmware. What it does is allow the firmware that is currently installed to use its expected defaults and variables. Highly recommended when the changelog indicates to do so, but also when flashing from stock to RMerlin firmware (or vice versa) to allow the respective firmware you flashed and want to use the best chance of seeing the changed variables and defaults it expects to. Even when moving from major version jumps of the same firmware, a full reset is usually needed/helpful to have a stable network. And occasionally, even moving from a .10 to a .11 release, it is required to fully implement the major changes that the .01 release brought.
3. There is no point in saving the config today, your network isn't stable or reliable in its current state. If you restore it, it is effectively like you didn't do the reset in the first place. The best use for restoring a backup config file is explained in the following link. But note that in your case here, you're not going to need it.
What you may want to do after fully completing this process, is create a Word/text file of the changes you've made past defaults, and save it for the next time this process may be needed.
I have had issues in the past when updating firmware and Internet speed, But it may have just been a fluke, Should I keep up with the updates? If so On all routers or the nodes as well? What about ones acting as access points? Thanks
www.snbforums.com
4. 5. I would power down everything in the network (including the modem/ONT). Remove all USB devices from the router(s). Remove all WAN and LAN cables (yes, I set up the router without being connected to the internet). When the router is secured and fully updated and set up with the defaults I want (see the links I proved above), then I power on the modem/ONT, wait for 5 minutes after it has fully booted up, then connect and power on the main router. At this point, I connect all wired devices, reboot the router, and test those devices again. Now I add the wireless devices one by one, testing them as I go. At this point, you should have a stable network with the router working and responding as expected. Only at this point would I add any nodes (and only if they are needed).
While the above seems like a lot of work, it really isn't. There is at most a 15-minute time period where you'll actually have no internet doing the above.
The following links may also be helpful to you to get your router/network to a good/known state.
After creating the checklists two weeks ago to save the pages with settings, I've made all the screenshots (I think at least) of all the relevant guides written by @L&LD and the very useful tip by @netware5. The only thing is, those guides are great, except when you'll be offline at least for a...
www.snbforums.com
www.snbforums.com
Top 10 Simple Asus/RMerlin firmware powered Router Troubleshooting steps to try first: NOTE: Although this is for Asus/RMerlin-firmware powered routers, the steps below may be relevant to all routers, to get to a quick fix for common symptoms. Check that the router’s System Time is accurate on...
www.snbforums.com