People often imagine that switching to a vegan diet (or otherwise avoiding dairy products) would mean missing out on chocolate, but it needn't be so - there are many good vegan dark chocolate bars around, in fact, and there are also several interesting vegan variations on the hot chocolate. Indeed, the hot chocolate consumed by the Mayans and Aztecs hundreds of years ago - quite bitter, often with chillies - was probably vegan. More in keeping with today's style of chocolate-drinking, hot chocolate turns out to be one of the things soya does very well; you can easily make a rich hot chocolate with soya milk (or oat milk) in place of cow's milk. Hot chocolate made with oat milk and soya milk mixed together, with brown sugar or maple syrup and plenty of cocoa powder, is at least as rich as anything that can be made with cow's milk.
To make a tasty, nutritious and filling food drink which is just on the sweet side of savoury, mix chocolate and hazelnut spread* with tahini and treacle or dark sugar and fine oatmeal, perhaps adding a little pear juice or apple juice, and heat it in a cup in a microwave or a pot on a low heat until it is just boiling, then heat it for about a minute and a half or so in the microwave (for a big cup), or simmer it for a couple of minutes on a hob.
To make a very satisfying hot chocolate drink without any milk or soya (or using only a little), mix together cocoa and cinnamon and perhaps some other sweet spice - nutmeg, cloves, cardamom - or a few drops of hazelnut oil or toasted sesame oil, with syrups like malt syrup and/or maple syrup and a little treacle, until you have a good thick paste; then add hot water. Optionally, coffee can be added (in which case you should leave out the treacle) or indeed tea - which makes a kind of chocolate chai. Stir well until the ingredients are good and mixed.
* Which of course is not always vegan, but there is a very good brand of organic vegan fairtrade chocolate and hazelnut spread called Chocoreale, and I'm sure there are various other kinds...