Can anybody suggest a knife sharpener that isn’t just an online trend or scam?

I need a knife sharpener. I keep seeing ads about online for that one with the magnetic block and rolling whetstone and tbh i do like the look of it, but the websites always seem so sketchy and reviews are very mixed.

Everything else seems too expensive, or too cheap to trust. Atm i have one of the old plastic knife sharpeners with the handle and slots that you run your knife through, but again, I’ve heard they’re actually not good for your knives.

Any advice for a sharpener that does the job and isnt too expensive. Ty.