The network name (SSID), security type, and passphrase must all be exactly the same. So you need to switch router 1 to WPA2-only mode to match router 2. And make sure their network names and passphrases are exact matches while you're at it. Capitalization, punctuation, spaces, accent-marks (diacritics) all matter.
Also please beware that your two routers aren't exactly on different channels. With 802.11ac's "VHT80" 80MHz-wide channels, it uses the old 20MHz-wide channels of 36+40+44+48 as one 80MHz wide channel. So you need to put your second router on 149-161 or a DFS (radar) channel (52 - 144) so their 80MHz-wide channels don't overlap.