I can and happily will second the A5 Rhodia Webnotebook recommendation. They're small enough for convenience, big enough for depth, sturdy enough to stand up to prolonged and heavy use, and full of beautiful Clairefontaine paper on which it's a positive pleasure to write. I've been using them for my diary for years now, and expect to go on doing so as long as I can still get them.
(Fwiw, I like a Decimo better than a Safari, although probably not as a first fountain pen - you want to start with a steel nib, which will be more forgiving as you learn a lighter hand, and the Decimo is both gold-nibbed and fairly expensive among pens that aren't coded "luxury". That said, if you're looking for a change, a Decimo is also light and comfortable to use, and durable in real-world use; I carry mine in my shirt pocket, and the only thing so far to give it trouble was a Labrador who was very excited to see me again for the first time in some years. Some folks do have grip trouble with the pocket clip, but all I can say is it's never bothered me, and the sheer understated elegance of the pen's design - in every way the opposite of the "look at me!" that a lot of more conventional pens convey - is a pleasure in itself, besides.)
Ooh, that’s a beautiful pen! The pocket clip seems like it’d serve the same purpose as the triangular grip on the Safari: “however you want to hold me, this is how you’re going to.” The Safari is the first pen that ever coerced me into holding it the “right” way (instead of my natural “lateral tripod” grip; see https://www.scoopwhoop.com/pencil-grip-names/) and I love it for that. Also, I’d be bummed if I lost my Safari, but seriously upset if I lost a Decimo.
But the Webnotebook is seriously wonderful with a nice pen and ink. It’s the perfectly level of minimal roughness that grabs ink while still feeling utterly smooth.
Oh, I worry about losing mine too, but if I'm doing anything that might pose a risk of it falling out of my pocket, I'll have my backpack with me and can stash it safely there. Other than that, it's either on my person, on my notebook, or in my hand. (Or in the car, if I'm visiting with my friends with the dog. I puppysat her for a week once, during what must have been an impressionable time in her youth - she greets me the same way every time as if it were the first time in years.) I might just be unusually good at keeping track of my things, though!
The clip is useful for the reason you describe, and that serves the user's purpose in a way I think most pen reviewers don't use a Decimo or Vanishing Point for long enough to discover. The whole design intent of the pen is that it should be easy and convenient to use entirely one-handed, and having the clip placed as it is helps the pen nestle neatly between the user's fingers as they change grip from "uncapping" the pen to writing with it.
After a while, just like with any other click pen, you barely have to look at it or even think about it to do it - I haven't done the latter in so long that I had to do the former just now in order to know how I use it at all. Most of the time I just use it. It's pure muscle memory at this point, and the clip is the only reason that can be true - not that the more deliberate process of preparing a conventional, round-sectioned fountain pen for use isn't pleasant in its own right, but the Decimo's lower overhead makes it much better suited to the way I think and write, as well as to regular carry and use with no need for special handling and no more need for special care than, say, my glasses.
(Sheesh, I should get Pilot to pay me a word rate...)
(Fwiw, I like a Decimo better than a Safari, although probably not as a first fountain pen - you want to start with a steel nib, which will be more forgiving as you learn a lighter hand, and the Decimo is both gold-nibbed and fairly expensive among pens that aren't coded "luxury". That said, if you're looking for a change, a Decimo is also light and comfortable to use, and durable in real-world use; I carry mine in my shirt pocket, and the only thing so far to give it trouble was a Labrador who was very excited to see me again for the first time in some years. Some folks do have grip trouble with the pocket clip, but all I can say is it's never bothered me, and the sheer understated elegance of the pen's design - in every way the opposite of the "look at me!" that a lot of more conventional pens convey - is a pleasure in itself, besides.)