will use their same frame, but put different components on it for models over a thousand dollar price range. So look at the product line for various manufacturers, and see what price points they change their frame material. For mountain bikes, you can also see at what points they change their shocks. Best to visit individual shops, and just see what geometry fits you, then decide what price point you want to be at (a particular dealer may only stock a few models from one manufacturer, and they'll push those, but they should be able to order any model).

If gravel trails are the toughest thing you'll ride, you may want to consider a gravel bike. These are basically road bikes with beefed up wheels/tires to ride on gravel. The advantage here is that you aren't paying for a shock you won't use.

You can also take your old bike and just get new after market wheels for it that'll be better than the stock wheels, and maybe even better than the stock wheels on a new bike.