expose local webserver behind dynamic IP

I've a simple webserver bound on 0.0.0.0:3000 on my machine which works as intended on local networks. By local network I mean to say, if my mobile or any other device is on the same network, it can access local webserver by going to the IP assigned to my machine and adding port 3000 to it. Eg 192.168.1.4:3000.

Now I've to expose it to the internet but not through some sort of 3rd party application like ngrok, localtunnel or browserSync. I know that these applications work perfectly, but since I've my own pet project of controlling home appliances, I don't want to rely on availability of 3rd party services. So the current state is, I cannot control it through the internet. Keeping in mind I don't have a static IP otherwise this would've been easier.

I already have a vps and a domain name assigned to it. I can send my currently allocated ip address (since it is dynamic) to my server and keep track of it. But how do I expose my local server to the internet through it? Those 3rd party applications assign some sort of subdomains to each exposed server, and I'll be able to assign subdomains too, but I'm still not getting any way to expose the local webserver. Any help would be appreciated, thankyou :)