Rasterize and problem with raster plot in R using "terra"

Question

I have a a problem to rasterize and mainly plot the result. We have a DEM with these features:

    class       : SpatRaster 
    dimensions  : 1600, 1600, 1  (nrow, ncol, nlyr)
    resolution  : 100, 100  (x, y)
    extent      : 605998.7, 765998.7, 5059499, 5219499  (xmin, xmax, ymin, ymax)
    coord. ref. : WGS 84 / UTM zone 32N (EPSG:32632) 
    source(s)   : memory
    name        : w48055_s10 
    min value   :     65.000 
    max value   :   3872.241 

Furthemore, I have a dataset on which I have created a SpatVector, as below:

pt_1 <- vect(dati, geom = c("Longitude","Latitude"), crs = "epsg:4326")
pt_1 <- project(pt_1, "epsg:32632")

    class       : SpatVector 
    geometry    : points 
    dimensions  : 1301540, 5  (geometries, attributes)
    extent      : 606000.9, 765847.5, 5059702, 5219496  (xmin, xmax, ymin, ymax)
    coord. ref. : WGS 84 / UTM zone 32N (EPSG:32632) 
    names       :   ID1  bio01 bio04 bio12 bio15
    type        : <int>  <num> <num> <int> <num>
    values      :     1 -1.375 590.7  1663 46.46
                   2 -1.342 589.6  1658  46.4
                   3 -1.333 589.9  1657 46.48

Once I try to rasterize them, the process seems work well, but the related plot has some problems.the problem is that the plot is not smooth and shows a strange texture even if I run the raster in Qgis.Initially I thought it was a graphical problem but I don't think so

cli <- rasterize(pt_1, demta, field = c("bio01", "bio04", "bio12", "bio15"))

What are the problems? The different size or did I forget something?