I'm looking into using Gotify with my NR flows to provide push notifications to my phone primarily. I have a number of sensors that are parsed through NR and want to push an alert if, for instance, the water leak sensor is triggered. I have looked at a lot of push options and I'm currently leaning towards Gotify as it's fully open source and can be run on a local server.
The problem I am having is that my internet provider does not expose my IP so it does not appear I can set up a forwarding option. I was initially going to set up a local server in a Docker container on my Synology NAS but that requires using an IP forwarder such as synology.me. But, as I said, that won't work.
Alternately, I believe the Gotify cloud should work but there does not appear to be a way to create a new user. I'm curious if others have gotten Gotify cloud server up and running on their NR and, if so, what were the steps?
Not used that.
I am personally not seeing the benefit?
If you are open to alternative ideas, many here use telegram. I am certain it can do all (and more) that you need.
it is a simple install from the flows library.
Not tried it. Most of us use Telegram I think.
To get a personal server working when you don't have an ISP with usable IP addresses is easily possible. You need to use an intermediate service. CloudFlare, NGROK or ZeroTier should all be suitable. They use an outbound connection from your server to create and maintain a connection.
Alternatively, with Telegram, you can use polling which again, uses an outbound connection.
I use Pushover - dead simple
I find Telegram a bit too geeky for my simple brain 
Personally I've stopped using Gotify in favor of using HomeAssistant's Mobile app's notification capabilities and they have a simple cloud/proxy option you can pay for if you can't access your home network via IP address.
Expanding on what @TotallyInformation mentioned you can look into some of the mesh VPN solutions like Tailscale, Nebula ect that will allow you to dynamically connect using a coordination server.
