With c you can:
-- Combine SpatRaster objects. They must have the same extent and resolution. However, if x is empty (has no cell values), its geometry is ignored with a warning. Two empty SpatRasters with the same geometry can also be combined (to get a summed number of layers). Also see add<-
-- Add a SpatRaster to a SpatRasterDataset or SpatRasterCollection
-- Add SpatVector objects to a new or existing SpatVectorCollection
To append SpatVectors, use rbind.