Vegan

I want to start eating more frequently plant-based foods, especially oats, lentils, chickpeas, etc. which are high on fiber. The thing is, I'm kinda hesitant to do so, because almost every time I eat them, soon enough I get the side effects for the rest of the day and the fact that I might spend a lot of time outside without going home doesn't help me.. (One solution would be to change some social norms around gas or feel less insecure.. I try to help others who are in my place to feel comfortable, but I don't know if others would do that for me🤷)

What could I do to help this situation? Is it possible for my body to digest it properly or will always cause extra gas?

Ideas I have read/thought so far (with some questions):

1. Soaking them in water for 12+hours and throwing the water. How many nutriens do I lose that way? How does it work? (I read somewhere that it simply takes away some sugars which cause digestion issues.) Does it work for all grains and seeds?

2. Putting them in a blender. That's kinda my idea, but would essentially cutting them in a finer and liquid state make them easier to digest? (Probably won't work at all for insoluble fiber though.)

3. Boiling/heating them up. Does this work? Does it degrade any nutrients?

4. Eating more. I've read that the gut adapts and digests them better over time. (Though I don't know how much improvement I should notice.)

I'd just like to minimize-eliminate the side-effects without ruining their nutrients if possible :)

Edit: Thank you everyone for your help! I see the main point here is to just eat more of high fibre food. Thank you for your time!😊