EDIT: Read this article in the context of getting stronger and you will be less inclined to pick a pitch fork up. I use dumbbells, kettlebells and even machines on a regular basis.
Out of all the the equipment you could chose to exercise with there is one that is far superior to the rest. That superior object is the barbell. Yes, thats right, the barbell is better than a TRX, kettlebells, BOSU balls (do I even need to say that? Sadly, yes.), machines, dumbbells or anything else you could possibly think of.
Why are the more superior? For quite a few reasons. To start they have the capabilities to essentially be loaded indefinitely. Meaning you could always add more weight to the bar. Which is good because that means you can always increase the stress you are using, you could add as little as ¼ of a pound at a time. And to get stronger (or bigger) you are going to have to increase the stress you put on your muscles overtime.
Barbells are also one of the most effective tools for performing basic and essential lifts to being a human (yes not just an athlete). Those lifts being the squat, deadlifts, bench press, overhead press and rows. Now there are more exercises and you could use other equipment to perform these exercises but a barbell is better. Let's take squat for example, we could perform them with kettlebells and do goblet squats, then we can use a barbell and do front squats (since they would be more similar to goblet squats). Now we could use bigger and bigger kettlebells but eventually we are going to run into a couple problems. One, eventually there won't be a bigger kettlebell; and two, eventually the jumps for one kettlebell size to the next might be to big. Most gyms that have kettlebells end around the 32kg mark or about 70lbs. They aren't going to have 70 lbs, then 75 lbs, 80 lbs and so on. However with a barbell we could increase the weight forever, at least up to more than anyone will ever be able to front squat. We can also increase the weights in smaller amounts than we could with almost any other piece of equipment.
They are also just cooler. Squatting 500 lbs, is cooler than squatting 130lbs using kettlebells (I don’t hate kettlebells they just make good example by the way, they are great for accessories to the barbell movements, AKA they do have a place).
They are more reasons I could think of why barbells are better but they would probably make this article too long for most people to read, so we will stick with those for now. Barbells are better because they are easily loadable and loadable indefinitely, making them more effective to perform a lot of the basic lifts, and since the weight is indefinitely loadable they make you look cooler because five 45’s on bar looks cooler than a 65lb kettlebell.