I’m no athlete, but I have seen some info on protein that may be of interest to you. Basically, at least for protein, Soylent should be perfect. Whether or not it is logistically convenient to carry around for training, palatable to drink after training, and whether the carb/fat content is ideal is another matter.
You don’t ever really need more than 1.6g of protein per kg per day. So if you weigh 75kg, and you have an athlete-level body fat percentage, you would be fine with 120g of protein. In fact, it seems like how you spread the protein out throughout the day is more important than the total amount you take per day.
How this relates to soylent: Most recipes I’ve seen, as well as official soylent target ~100g of protein per day for 2000 calories. If you are eating enough to cover a 3000+ calorie diet, then you will likely have more protein than your body can utilize. (exception: if you’re 95kg or more and only need 3000 calories or less) Due to the nature of a homogenous drink, it is going to be spread out very evenly without any special effort, which is even better.