Figure out how to hack your satiation (it is very different for different people), and you have started to unwind the stack on how to address your intake challenges. Start your rabbit hole research with the search string "long term induced satiety" (but without the quotes), and branch off from there. That starts you off with physical and chemically-constrained satiety, but there are cultural, mental, social, financial, and many other factors at play as well that might be dominant in your particular situation so go in those directions if it makes sense to you. YMMV.
You intestine cannot extract every calorie, especially those in unprocessed (fiberous) plant cells get excreted.
I find eating more helps me: eat more volume/weight, of less calorie dense foods. Diets like WFPB and raw mornings-and-or-afternoons do that for me.
Good luck finding many foods like that or enjoying them though.
Also: not trying to lose weight, more trying to build some :)
It took some serious lifestyle changes for me to become and stay in shape - and habits _are_ a hard thing to change. ;-)
I think, from my experience and from the experiences I've read of people who have lost weight and kept it off, the key is finding a sustainable diet. One that your future, goal-weight self can be trusted to follow even after you're done losing the weight. People tend to get to that point and then go back to eating like they did when they were overweight, which reverses all the hard work they did.
Telling someone to eat less to lose weight is technically correct, but in reality is useless advice. And no, it really is hard.
Maybe if you got lucky with a great metabolism it might be easy, but a lot of people don’t have that and will struggle.
It’s not about eating less and more about eating correct.