2500kcal is only suitable for people living a very active lifestyle or exercising a lot. Note that going to the gym for 45minutes 3 times a week is not being active.
When I spent an hour lifting heavy weights 5 times a week, my weight was stable at around 2500kcal.
The reality is that unless you work as a construction worker or other type of job that keep you active most of the day and/or exercise a lot (my 5x a week were heavy compound powerlifting lifts), chances are you need to adjust those recommendations down substantially.
Ultimatly the only thing you can do is to gradually lower your intake until you're losing weight. That you were adding weight at 2000kcal is not that surprising.
I've not tried Soylent, but I've trued Huel, and compared to what you described it seems a lot more pleasant, and more importantly, if anything I've found it hard to eat enough on it because it fills me up so much. The biggest problem for me in using it as much as I'd like is that filling me up doesn't stop me craving food - it's a reward thing for me.
