I am not a Doctor, nor a medical professional...
How much time you have to spend cleaning up afterwards, may be a good indicator of where your fiber intake needs to be relative to the rest of your diet. In the aftermath of a perfect meal, a few wipes should have you back in status.
Hydrated chia is my preferred option - it travels well in dry form, hydrates quickly, does not gunk up bottles as other options may, and it also jives well with rehydrant tablets when both are indicated. It can also be added to most stews and soups without noticeable change to texture or flavor, and mostly integrates with oatmeal and the like.
Most forms of plussing up the fiber absolutely need hydration; the consequence of taking shit dry or minimally hydrated include nasty cramping in the GI at one end, up to a full blockage at the worst case end of things. Being easy enough to avoid, hydrate your fiber before consumption.
Best guidance for plussing up the fiber is to make its' intake as regular as eating food is - which requires making it convenient, accessible, and viable to take it contemporaneous with consuming the rest of the meal. If that means developing the habit of shaking up a batch in a bottle as you begin foodprep, or before you walk into your food provider of choice, then the habit must begin forming now. If one likes to drink it down contemporaneous to the eating, have it available and begin inculcating that pairing.
Considering fiber intake with the same scrutiny that some have with their sugar\protein\carb\etc intake can have advantage beyond just the shittery. Using fiber additions to stretch out the benefit of meals, reduce the peak\jitteriness\crash associated with a high sugar or protein intake, or moderate the realities of high protein diets may be of benefit to most.