In reply to Sabilly1:
Touring bikes have traditionally been used with pairs of panniers on racks to carry your load. They're predominately used on roads although members of the Rough Stuff Fellowship and other cyclists like Ian Hibbell rode millions of miles on gravel roads (and worse), all over the world throughout the hundred years before gravel bikes and bike packing were invented.
So a traditional touring bike is very versatile and I have used mine on unpaved roads throughout the Alps plus criss-crossing Europe on tarmac. The more voluminous panniers allow the carriage of more regular camping gear and are easier to pack and unpack.
Gravel bikes are similar in many respects, but have fatter tyres and often run tubeless so lower tyre pressures can help with absorbing the roughness of gravel roads. But although you can pick your way through surprisingly rough terrain, there's no denying that there comes a point when things become easier (and faster) with suspension. The bikepacking bags are undoubtedly more stable and durable when bouncing around off road but they are expensive, a pain to pack and limited in volume which steers you down the lightweight, minimalist, expensive, spartan gear route.
As to gearing, cyclists use a system of 'gear sizes' that removes all the variables of sprocket tooth numbers, wheel sizes, chain ring size, etc. Old fogeys still use the inch system but others will use a different metric system to achieve the same aim. You'll read about it on bike websites and there are numerous on-line calculators where you can enter the variables and it gives you the important output. For loaded touring in hilly terrain it's generally accepted that having a gear less than 20 inches ( less than 18 ideally) gives you more options when the going gets steep / long / well loaded. I've seen review after review of gravel bikes with nothing less than 24 inches.
So if you view bikes as being on a continuum from racing bikes at one end through to full suspension downhill mountainbikes at the other, both touring bikes and gravel bikes are in the 'middle' on the transition from road to off road. Touring bikes are a little more 'road' and gravel bikes slightly more 'off road'. Only your needs will dictate whether either works or, like the rest of us, you need more than one bike. (Sorry)
PS - I've read you have a full sus, so I think your choice is easier. That Giant you have highlighted would complement it, but is more aimed at leisure riding on canal tow paths and forest roads. If you compare it to the offering from Spa Cycles ( https://spacycles.co.uk/m1b0s225p2983/SPA-CYCLES-725-Steel-Tourer ) you will see something comparable, but with a more on-road touring focus. I think it illustrates the different emphasis.
Post edited at 21:51