There are many different types and styles, mainly front or rear lounge, kitchens can be front back or central as can bathrooms, you also need to think about where it will be parked, how long can you easily park on the drive at home or will it need to go into storage, there is a weight issue too, over 3.5 tons and you need a different licence.
I would get to a few dealers, go into a van you like the layout of and sit there quietly imagining how you might use it, where you would put things, see if there is anything you might find difficult to do, and then go home and discuss it, maybe go look at some others, take a few pictures of the ones you like most
Don't get too hung up on what extras they have solar isn't too expensive and is an easy enough DIY job but if you will mainly use campsites then you may not need it, refillable gas is handy to have but again can be a DIY job to fit.
We started off with a tiny rear lounge van and quite liked it but we've have both front and rear lounges over the years big and small vans too.
How you use it will be the biggest thing to consider, and how long each trip will be, longer means perhaps you need more storage, try to get low down storage for tins and jars etc, a decent wardrobe for dresses etc, so many aspects that your simple question needs a lot more thought to be answered fully.
But we're here to help, and best to ask before spending thousands on the wrong van or accessories after buying one.