So I have 100+ websites I manage for various clients, and it is a pain for me to login to their hosting or domain registrar accounts to manage their DNS.
Is there a simple solution, where I can turn on my own server that manages DNS? So for every domain I manage, I simply set a DNS once as ns1…com, and from thereon I can just manage their DNS configurations?
You can always use a Pi-Hole which offers DNS Hosting or if you have a Synology NAS
https://pi-hole.net/
https://dnssimple.com is also a great cheap solution that will host your own NS servers.