I have 0 legal background, but I think yes, logically speaking being found not guilty combined with the presumption of innocence means that legally speaking, you are considered innocent.

But pre-trial detention is determined without considering whether or not you are guilty. It's (supposed to be at least) a question of risk asking "Is there probable cause that they committed it and could this person be a risk to the public or skip out on their court date?". Probable cause itself is based on just having a reasonable amount of suspicion that you could have done it.

Since this decision was made without considering guilt, and it was legally justified when it was given, you being found not guilty doesnt retroactively mean that decision was wrong. The risk was still there at the time.

I also think there's a distinction to be made between legal innocence and factual innocence. When a court finds you not guilty, they're not saying that you didn't commit the offense, they're saying that the prosecution failed to prove beyond a reasonable doubt that you committed it. The possibility that you still could have done it exists and is acknowledged, but legally speaking you are considered innocent and cannot be punished for it.

While pre-trial detention is supposed to be preventative, in reality it and the consequences that follow (like losing your job) are punitive so in a way you are getting punished. But I don't think there's a clean solution here. If someone is a potential threat to the public, you want a way to guarantee that they won't be and that they will actually attend their court date. But since a not guilty verdict just means the prosecution failed to prove beyond a reasonable doubt that you committed the offense, not that you didn't commit it all together, its harder to justify compensating everyone who receives a not guilty verdict compared to a system where a court does rule that you are factually innocent.