Any affordable air purifiers with responsive, functional air quality displays?

I need an air filter for small to medium room but just tired to find cheap units with useless fake air sensors. By “cheap” means around$50-$100. Not real fake ones.
My last purifier stayed on green light even when I’m frying food or the room was covered with dust. The auto mode never adjusted the fan speed automatically, so I guess the sensor feature was just a gimmick. I don’t quite need a smart one or big unit, just something around $100 and can do its job. Like a real numerical PM readout score, not just a green or yellow light. A real auto fan that can adjust its own speed when air quality drops. Would be best to have affordable replacement filters and sufficient cleaning power for a bedroom or a small living room.
Any suggestions or recommendations for a budget friendly purifier that actually works as advertised? I was checking several budget lines of big brands and MOOKA air purifier, but the online reviews are quite variable across every line or brand. Would appreciate any real user feedbacks!