In Australia both Signal and WhatsApp are free, aside from using the data service rather than the "telephone" service, and we pay for a monthly or annual data quota with our phone plan.

Do you have separate charges for Signal and/or WhatsApp?

Yeah I guess I confused a lot of people: the charges are for the data, not the app. They are tiny, but if you use the app heavily and rely on it, you don't want to be disconnected when your data runs out.

You pay for signal? Which bit of Europe are you being ripped off in?

I read this as a phone contract having a bundled: unlimited whatsapp, Spotify, Facebook bundles where data usage is not counted towards your total data allowance in the contract. For example in my country in the middle of Europe you have bundles with unlimited traditional communication and 20 50 80GB of mobile data.

When you WhatsApp all day sending videos, gifs, messages, voice messages, pictures, documents..I can consume up to 12GB per month, this costing me an amount of my 20GB data plan. While a other provider I can choose has a 20GB data plan with a unlimited WhatsApp bundle. Sadly they don’t offer eSIM and 5G so it’s a no go for me.

Not sure where in Europe you're from but in the Netherlands WhatsApp and the likes are just considered Internet usage, no special costs.

Wait… in Europe it costs money per app somehow on a phone? Or for data?

In the US I get similar benefits with YouTube and T-Mobile. The soft data cap doesn’t count YouTube at 480p in the data usage calculation.

Without net neutrality many providers favour the incumbents.

Is it still impossible to use Signal without phone ? That's the biggest stopper for me

Yes. You are identified using the phone number.

This has been a big downside for years, I'm surprised it hasn't been fixed yet. Your account has to be tired to a phone number (though you can use voip) and only their mobile apps act as a primary that can register the account.