Well first in regards to the database (not about changing the sources) that surely will be impacted by the IP address change and can only be fixed by either a rescrape or the path substitution.
But yes 4 Mbps wifi indicate something is wrong. In normal environments the Vero4k Wifi should perform much better.
- Do you have 5ghz and 2.4Ghz with separate SSID? Otherwise the Vero might be connected only to 2.4Ghz
- Has something else changed recently? Could you temporarily try with Ethernet?
Check this
Maybe something changed in the network, we suggest to check your network with iperf3. Please read this howto