Years-long plateau with FitnessBlender?

I've used Fitness Blender for years and I love it; it has helped my performance a lot from when I could barely get through a video. However, whenever I see anyone's before and after FB pics (though yes, I know those can be misleading), I'm a bit disheartened at my own lack of progress. I also think I've stopped making strength gains, as I use my same set of PowerBlocks for everything (but they only go up to 24 lbs, plus some extra weights I pile on sometimes).

I've completed various FB programs multiple times (Abs, Burn, Strong, and Fit Round 2), but never throughout any of these programs have I had any visible differences before and after. I never thought much of it because I figure making body changes takes time, but reflecting on the fact that I've been stuck in the same place for years I have to wonder. I always have about the same amount of stubborn belly fat covering my abs -- am I genetically doomed to stay like this? I've lately been thinking that it's more to do with diet, but I try to eat pretty healthfully (I'm also vegan) to little apparent avail. Even cutting out sugar for a month didn't do anything for me. I've lately sort of tried to be more in a caloric deficit (I usually and even still eat quite a lot) but this just makes me feel even weaker during my workouts.

I workout 5 times a week (as per most of the FB programs) and do stretching or yoga on weekends. I don't do excessive loads of cardio or HIIT either, as I mostly follow the FB programs, or their format at the very least.

On a slightly different note, am I the only one who is dubious about the efficacy of the amount of weight you can lift at home when compared to the hundreds of pounds people (even women like me) can heft at gyms? Like, squatting 48 lbs total is my max -- is that not a bit sad? Do other FBers get more out of their workouts?