Benriner mandolin is the standard for chef’s worldwide (no need to sharpen, blades are cheap and easy to replace). I use it more than my pairing knife.
Shun made a really high end one at around $300, several other brands have their own versions. Essentially it’s a razor blade with an adjustable gap, nothing fancy needed here. Trust what you’ll find in professional kitchens, cheap and simple is sometimes the best solution. (It does come with a finger guard plastic device but have honestly never used it).
Benriner Japanese Vegetable Slicer
https://www.amazon.com/dp/B000BI8EDG..._DtZtCbHJ41X0E