AdGuard-DNS DDNS, how do I set it up?

[dnszola]

I need to use AdGuard DNS only on my Android phone, and I'd like to set up DDNS.

I can't find the section to enter the DDNS host in the AdGuard DNS dashboard. Could you please guide me? What should I do?
I'd like to let you know that I want to use its VPN and not change my Android's private DNS settings.

Another questions: is the app required for AdGuard DNS to work, or is it possible to do without it?
What do you think is the best free DDNS host to use?