I used terra (version 1.7.71) to read the nc4 files.
However it notice that:
Error: [rast] cannot open this file as a SpatRaster: /Users/aa/Desktop/data/MERRA2_400.inst1_2d_lfo_Nx.20230126.nc4.nc4
In addition: Warning message:
`/Users/aa/Desktop/data/MERRA2_400.inst1_2d_lfo_Nx.20230126.nc4.nc4′ not recognized as a supported file format. (GDAL error 4)

rast("MERRA2_400.inst1_2d_lfo_Nx.20230126.nc4.nc4") -> rst
plot(rst$TLML_24)