Upgrading a entry level hybrid bike or purchasing a new better one

The bike looks like it should be fine for light trails. I have an old hybrid with no suspension that I use on light trails and It's fine as long as I don't try to push it too much on technical sections.

I think you'll always have some problems with trying to find a single bike that works well on trails and roads as there will always be some trade offs. You might want to consider having 2 sets of wheels, one for roads, and one for trails. The stock tires don't look like they are suited for either and are somewhere in between which means they won't perform optimally anywhere. Having a second set of tires would be okay as well, but having whole wheels are a lot easier to swap out.

I wouldn't try to upgrade to something with more gears on the cassette as things can get expensive quickly because so many different components need to be changed.

• Upgrading an existing bike piecemeal is always going to be more expensive than buying a new bike with the specs you want, because manufacturers get components at a discount.
• Regarding Option 1, upgraded components will not transmit more stress to the frame, if that's what you're asking. It is possible (but seems unlikely) that the frame was engineered with just enough safety margin to allow for light trail riding, but not more intense off-road riding. I wouldn't let that guide my decision.
• The gravel-bike category is a broad one, and some bikes are more road-ish, others are more MTB-ish.
• If you frequently cover both tarmac and dirt in a single ride, that sounds like a good argument for a gravel bike. Everything is a compromise, and you need to figure out what compromise you're most comfortable with.

Ragarding the choice of bike if you decide to replace rather than upgrade.

It does sound like you need a sort-of dual purpose bike that can tackle easier trails but not be too heavy or low geared for road use. I recently discovered that some manufactures are making ’flat-bar gravel bikes’. These essentially look like rigid fork MTBs from the 90s but with modern components. You can find them with gravel bike like ~40mm tires on 622 rims or MTB like ~2” tires on 559 rims.

I'll get out the way the idea that you need a special bike for each type of trail - you don't. Any bike can be used on any ride, its just some are better than others, welcome to the definition of compromise.

I do not believe the X-caliber is the right bike for you - its a technical bike designed for aggressive single track riding and racing over an hour or three. Its not designed for long tour comfort and is the wrong design for a good gravel road bike. Putting a bigger chainring is the least of your worries with regard to making it more suitable for road, gravel and long distance.

That leaves a hybrid, gravel or adventure bike - decide if you want drop bars or flat bars of something else. Personally for 800km with flats would not be my choice.

If you want a technical single track capability in one bike, then (IMHO) the best way to do it in one bike would probably be a bike that runs 29" (700C) for road, swapping in 27.5+ for single track. Gravel rides could use either wheel set - depending on the type of gravel road your facing. Problem is still the bars - you want flats for technical rides, but need multiple positions for long rides.

Aftermarket bars come in all sorts of varieties - two designs worth looking into for ideas are the Velo Orange Crazy Bar and Surly Moloko - these are just two of many variations of flat bar that give alternate hand positions.

Or you have two bikes....

I'd like to focus on an aspect that seems overlooked here -- the wheels. In my experience, bike makers like Trek often save money by providing less durable wheel components, as buyers are often less familiar with hub, spoke and rim designs. The fact that you are getting broken spokes suggests to me that the spokes were not properly tensioned or the rim or lacing isn't appropriate for your use.

A different wheelset can make an enormous difference to your ride, and with a few on hand, you can easily choose which wheels/tires make sense for that day.

You can easily order a custom-made wheelset or a stock one more suited to your uses. Many local bike shops have good wheel-building skills, allowing you to select hubs, spokes, lacing pattern, and rims to best fit your needs. Probably a bit cheaper will be some online vendors, but you want to have any wheels shipped to you to be checked by your LBS to make sure the spoke tension and other assembly details are correct.

I think you'll be surprised how big a difference a wheelset change can make.