dydns vs registering a domain

I have used dydns for years so that I could get to a VPN server on my network.

This has been invaluable quite a few times.

However my subscription has run out and I am trying to figure out if it is worth updating (US$50/yr)

I now have a fixed IP for my fibre (CG-NAT killed dyndns) with 2Degrees.

I still need my VPN

I would like to run a small web server (I am running 2 OSX servers, so have Apache, etc) to document my computer collection (around 400 machines from the 1970's - 80s in various states of repair). I have my own DNS (we have over 50 networked things)

I own RapidWeaver 7+ Stacks + Platform and would create my site myself (learning opportunity)

All this can be achieved with dyndns, however I am wondering if I should get a "real" .nz domain, long term it will be cheaper

Anyone here doing this, running a server at home with their own domain

Any gotchas , hassles , costs (apart from the domain name) ?

I am by no means an expert , I know enough to be dangerous LOL, so any information would be much appreciated.

Any thoughts on registrars ?

TIA.