This なくす is used when we lose something tangible.
財布を無くす lose a wallet
鍵をなくす lose a key
ペンを無くす lose a pen
This なくす is used when we lose someone.
*This is a transitive verb. Always someone who is deceased is the object in the sentence and I is the subject.
去年、母を亡くした。 I lost my mother last year.
長年の友達を、がんで亡くした。 I lost my long time friend due to cancer.
祖父を事故で亡くした。 I lost my grandfather due to an accident.
This うしなう is used for both tangible and intangible objects and even person. Mostly for intangible objects.
コロナで仕事を失う lose a job due to Covid19
嘘で信頼を失う lose a credit because of a lie
気を失う faint, to lose consciousness
光を失う lose light = to lose one's eyesight = to be blind
興味を失う lose interest
意欲を失う to lose motivation
For tangible objects, なくなる is more daily use. When you use うしなう for tangible object, it sounds serious matter.
Sentences below grammatically work , but it sounds exaggerated.
手袋を失う lose gloves
ハンカチを失う lose handkerchief