Noob Setup

Hi, tech-noob here. I've set up my Mac with NextDNS, but I wanted to make sure I have all my bases covered. Questions:

1) The Configuration Profile shows under Network > VPN > Filters & Proxies. I've enabled it there. Is that it? (My security settings seemed to work fine even when it was "disabled").

2) Do I need to add DNS-over-HTTPS? If so, where do I add this—my Mac, my router, each browser...? And do I just input https://dns.nextdns.io/48883e or have to add a name to it too?

3) Will different Profiles that I set up through the dashboard automatically work, or will I need to upload them with a new Configuration Profile (via https://apple.nextdns.io)?

4) If I want to set up our phones, do I access the site directly or use the Short Link or QR code?

Thanks for the help!