The tinkering is more down to the desktop app being great for getting started but that tunnel option is something we don’t tend to recommend for live environments as it has the issues you are seeing.
We have some documentation on self hosting but I think if there is maybe a limited budget this guide from @MutedJam on using Oracles free tier is very good: Setting up a free n8n server on Oracle Cloud – Thomas Martens
Another option could be to try something like nip.io which can be very handy if you don’t need to access it from the outside world. You can set the webhook url to the nip.io address and it would be good to go there is an example on how to do something similar with Desktop and ngrok here: N8n Desktop custom Webhook url ngrok - #4 by Jon
Once you have one of these sorted it will be plain sailing and you shouldn’t run into any other issues.