Thanks very much!, when the router assined to HA the IP that i want, then I fixed it with the second option that you answered me.
Ok, I have my Raspberry Pi 4 for Home Assistant together with my two NAS and a switch attached to a UPS. The IP addresses are static for all three devices and they use addresses that arenāt used by the DHCP of my router.
If the power is away I still have the IP set in my Home Assistant and my two NAS to let them communicate with each other because after 10 minutes Home Assistant switches off both NAS.
So, I thought I was having IP conflicts on my system. That turns out to not be the caseā¦
When I set up AdGuard as the DHCP server, I changed the range. It recorded several devices trying to connect (which, I had deleted and wiped a bunch of these switches, whatever). It set up new IP addresses for everything, but NOTHING connects to the internet. My phone just says, āConnected, no internetā
Someone mentioned an upstream DNS:
Iām basically at the point, Iāve given up and went back to Google WiFi, giving the corporate Giants all my data 
Hello. Looking at your configs, I think your DHCP range is on the wrong subnet. If your gateway is 192.168.86.x, and your Subnet Mask is 255.255.255.0, you DHCP range should also be on 192.168.86.x and not 192.168.83.x.
I have a similar question. I changed the static IP of my HA and changed the IP range of my router later on (Long story) Now my HA is disconnected and I donāt know how to change the HA static IP again. Will the USB stick method work? Mine is not a new HA installation! Appreciate any help. Thanks.
You can set you computer to the old IP range and connect to HA like before. You only have to use an Ethernet cable directly between the computer and HA.
Thanks. So plugin the ethernet cable from the HA to the computer? Let me try that
That worked. Thanks.
Now I am having trouble accessing HA from outside. I have DuckDNS setup. Made all the port forwards as previously. Not sure why I canāt connect from outside!