DO NOT USE EPSG:4326 EVER!

[rsbivand]

Please leave all files extracted from authorized government sources with their original coordinate reference systems. EPSG:4326 is a datum ensemble which fudges dependence on a particular temporal specification of the CRS. The ambiguity shows when sf is buiilt against PROJ >= 8. GDA94 and GDA2020 are well-known representations and may be incorrectly transformed to other representations if transformation grids are not used. I assume the input data are from https://www.abs.gov.au/statistics/standards/australian-statistical-geography-standard-asgs-edition-3/jul2021-jun2026/access-and-downloads/digital-boundary-files or similar.

$ PROJ_NETWORK=ON projinfo -s EPSG:7844 -t EPSG:4326 -o PROJ --spatial-test intersects
Candidate operations found: 3
-------------------------------------
Operation No. 1:

EPSG:8450, GDA2020 to WGS 84 (2), 3.0 m, Australia including Lord Howe Island, Macquarie Island, Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Norfolk Island. All onshore and offshore.

PROJ string:
+proj=noop

-------------------------------------
Operation No. 2:

INVERSE(EPSG):9690, Inverse of WGS 84 to GDA2020 (3), 3.0 m, Australia including Lord Howe Island, Macquarie Island, Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Norfolk Island. All onshore and offshore.

PROJ string:
+proj=pipeline
  +step +proj=axisswap +order=2,1
  +step +proj=unitconvert +xy_in=deg +xy_out=rad
  +step +proj=push +v_3
  +step +proj=cart +ellps=GRS80
  +step +inv +proj=helmert +x=0.06155 +y=-0.01087 +z=-0.04019 +rx=-0.0394924
        +ry=-0.0327221 +rz=-0.0328979 +s=-0.009994 +convention=coordinate_frame
  +step +inv +proj=cart +ellps=WGS84
  +step +proj=pop +v_3
  +step +proj=unitconvert +xy_in=rad +xy_out=deg
  +step +proj=axisswap +order=2,1

-------------------------------------
Operation No. 3:

INVERSE(DERIVED_FROM(EPSG)):9691, Inverse of WGS 84 to GDA2020 (4), 3.0 m, Australia - Australian Capital Territory; New South Wales; Northern Territory; Queensland; South Australia; Tasmania; Western Australia; Victoria., at least one grid missing

PROJ string:
+proj=pipeline
  +step +proj=axisswap +order=2,1
  +step +proj=unitconvert +xy_in=deg +xy_out=rad
  +step +inv +proj=hgridshift
        +grids=au_icsm_GDA94_GDA2020_conformal_and_distortion.tif
  +step +proj=unitconvert +xy_in=rad +xy_out=deg
  +step +proj=axisswap +order=2,1

Grid au_icsm_GDA94_GDA2020_conformal_and_distortion.tif needed but not found on the system. Can be obtained at https://cdn.proj.org/au_icsm_GDA94_GDA2020_conformal_and_distortion.tif
$ PROJ_NETWORK=ON projinfo EPSG:7844
PROJ.4 string:
+proj=longlat +ellps=GRS80 +no_defs +type=crs

WKT2:2019 string:
GEOGCRS["GDA2020",
    DATUM["Geocentric Datum of Australia 2020",
        ELLIPSOID["GRS 1980",6378137,298.257222101,
            LENGTHUNIT["metre",1]]],
    PRIMEM["Greenwich",0,
        ANGLEUNIT["degree",0.0174532925199433]],
    CS[ellipsoidal,2],
        AXIS["geodetic latitude (Lat)",north,
            ORDER[1],
            ANGLEUNIT["degree",0.0174532925199433]],
        AXIS["geodetic longitude (Lon)",east,
            ORDER[2],
            ANGLEUNIT["degree",0.0174532925199433]],
    USAGE[
        SCOPE["Geodesy, cadastre, engineering survey, topographic mapping."],
        AREA["Australia including Lord Howe Island, Macquarie Island, Ashmore and Cartier Islands, Christmas Island, Cocos (Keeling) Islands, Norfolk Island. All onshore and offshore."],
        BBOX[-60.55,93.41,-8.47,173.34]],
    ID["EPSG",7844]]