Pallbearers are pallbearers.
They may be relatives or they may not be relatives. In most of my own families, pallbearers were generally relatives–with an occasional neighbor or two thrown in the mix. Pallbearers were frequently nephews or cousins (or the spouse of a niece or cousin) with the occasional neighbor thrown in the mix. Choosing them was usually a negotiation in keeping various extended family members from feeling left out.
Other families have different practices and when your research takes you to a different geographic area, time period, ethnic group, social class, etc. then the practice may be different than what your own immediate family did.
Do not assume everyone operates the way your family of origin did.
That’s good advice across the genealogy board.