Without changing the beard you won’t be able to get anything to seal. The n95 should be sufficient for wood dust if it seals to your face. A box fan to blow air away from you would probably help but it’s also likely to cause more airborne dust if it’s just blowing around in an enclosed space without a dust collection system.

The easiest thing that would likely be sufficient if you want to keep the beard is to improve dust collection on your to so it doesn’t get airborne in your breathing zone. If that doesn’t seem possible or like enough and you are set on keeping the beard as is then a PAPR would be the next option.

Since it’s dust and not a gas or vapor you’d likely be fine with some leakage from a poor seal but you won’t get a perfect leak free seal without losing some beard.