The question is a bit broad, and it is a bit complex to answer. In the end, it is probably more a thing about expectations vs reality.
Every resampling algorithm tries to guess what a new pixel between two existing ones should look like. In some cases, they average the values around, so the result is hiding the pixels behind a blur.
Sometimes that is just what you need. Not having distracting pixels. If the image is interesting, this slight blur will not distract you as much.
Newer AI algorithms try to make better guessing by analyzing the context and the relationships between pixels, not only the adjacent ones, but along some patterns, for example, they try to see if the pixels are from a sharp contrast zone.
In my opinion, I only would resample an image at exactly 200%, and only to hide an already small pixel. For example, in most cases, I consider a print of 100PPI good enough, even to be viewed close, let us say 30-50cm. But to avoid seeing the pixels on sharp edges, I double it, having a final resolution of 200PPi.
The point is not trying to fool yourself into thinking that you achieve great sharpness only by resampling an image.