re: So I got two routers on my network now, but having speed issues

If you put the 2.4 and 5 GHz bands on separate SSIDs, do you get full coverage throughout the house on every device with a 5Ghz-capable adapter? If so, I don't see the problem with putting the two bands on separate SSIDs, keeping your 2.4GHz-only devices on the 2.4GHz SSID, and your 5GHz-capable devices on the 5GHz SSID.

When both bands use the same SSID, your device prioritizes the bands. Obviously the 2.4GHz-only adapters will only use that band. For the dual-band adapters, it will generally only prefer 5GHz when the signal strength is better than the 2.4GHz, because the 2.4GHz has a longer range, assuming there is no interference. The only benefit of 5GHz is the lack of interference with the many devices that use 2.4GHz. Of course, band hopping is only a temporary fix, since the problem returns when everything starts using 5Ghz.

If you list your devices, which routers/bands they connect to, and in what rooms they are performing poorly, that would give me a better understanding of what's happening. At a minimum, though, I recommend separating the SSIDs by band so you can see where your connectivity is poorest on each band and each device.