If I cancel the subscription in the future, can I still use my personal domain name for myself?
In brief, “yes.”
If you buy your domain name, you own it. There are some nasty, evil, malicious, cruel, and possibly Satanic companies that sell you domain names but register them as their own, effectively “leasing” you the name. Avoid them like a sneezy aunt with the Ebola virus. I know Verio does not do this, nor do many others. Check to be sure your domain name seller does not.
You can change where your domain name points at any time. See, a domain name, like “mimetic.com”, simply points to a server somewhere, like a sign. Changing the “DNS name server” just changes which server your name points to, like turning the sign. You can even keep your gallery subscription, change where domain name points, and choose a new name for the gallery.
Unless we bought the domain name for you (and you do not have the username/password to modify it), then we have no control over your name at all!