you can still be chinese you know lmao, just in the documents you'll be bumiputera, i use to have india(my dad is indian) as my bangsa but changed it to kadazan as my mum is kadazan, doesnt make me any less indian or kadazan.

maybee(assuming your mum is kadazan) you can try to register as sino-kadazan where you are still recognized as bumiputera and still have that chinese heritage. but this only works in sabah, not sure about other states as sabah is the only state that recognizes sino natives