بسم الله الرحمن الرحيم
It is not lawful to trim the beard less than one fist. Yes, if your beard is longer than one fist then you may cut the extra beard to embellish it, it is allowable as per the Shariah. Likewise, you may also trim the hair of the cheek with scissors or razor beyond the beard limit. However, you should comb your beard regularly and apply oil which may make your beard beautiful.
لا بأس بنتف الشيب وأخذ أطراف اللحية والسنة فيها القبضة (در مختار مع الشامى 9/583، ط: زكريا)
Allah knows Best!
Darul Uloom Deoband