You’re right to go 2x for a multi-use bike, especially if you’re going to end up with separate road and gravel wheelsets at some point. 10-42 or 11-42 cassettes just don’t quite have the range to do both the steepest gravel climbs and keep up with a brisk road ride on the same chainring. 1x is a great setup for single use but I didn’t fancy swapping chainring sizes on the regular so I went back to 2x for my multi-use bikes. It was fine on the road if I was riding solo, but became frustrating in a group.
Worth checking out the Vitus Substance. Sora spec version would leave you budget to spare for tyres/mudguards/etc. if your size is in stock. I’ve got last year’s version as my commuter / my partner’s bike and it’s decent. The GRX400 version has wheels and chainset that I think you’d struggle to find elsewhere at that price point if you’ve got loyalty discount, but may be out of your budget.
And I’d have a look at Merlin’s own-brand offerings as well, though I don’t personally love the spec sheet on anything listed at the moment.
Wilier linked above seems decent, but it looks like it’s a QR rear wheel, which would put me off it. Boardman mentioned above is a great package and I’ve got a few clubmates who are really happy with theirs.
Of course Ti is fun and lush and may be just the thing to inspire you to get out and ride, but PlanetX says max tyre is 35c. Sounds like Splash thought you could go bigger, but if not then it’s never going to be able to push beyond ‘allroad’ to ‘all day gravel bike’, which may or may not be fine depending on your needs.
If you end up with TRP Spyres (or any cable disc brakes) and find them disappointing then re-cable them with compressionless housing. It makes an enormous amount of difference & I think it’s shocking that brands aren’t willing to spend a few pence extra to put it on bikes as stock.
You mentioned somewhere that 11kg was too heavy - I don’t think you’re going to get under 10kg at this price point. My custom Ti bikepacking bike with GRX810, carbon wheels, finishing kit, etc. is nearly 10kg and my carbon gravel race bike with the same groupset, wheels, etc. is nearly 9kg - that includes pedals, bottle cages, etc. so not a direct comparison, but it’s just to say that this kind of bike is going to be ~1000-1500g heavier than an equivalent spec disc brake road bike and probably even a bit more when compared to rim brake bikes.
Of course everything I’ve said is subjective, YMMV, etc.