  The large amount of data recorded with the ATLAS detector at the Large Hadron
Collider, corresponding to 140 fb$^{-1}$ of $pp$ collisions at a centre-of-mass
energy of $\sqrt{s}=13$ TeV, has brought our knowledge of the top quark to the
next level. The measurement of the top$-$antitop quark pair-production
cross-section has reached a precision of 1.8% and the cross-section was
measured differentially up to several TeV in several observables including the
top-quark transverse momentum and top-quark-pair invariant mass.
Single-top-quark production was studied in all production modes. Rare
production processes where the top quark is associated with a vector boson, and
four-top-quark production, have become accessible and precision measurements of
several of these processes have reached cross-section uncertainties of around
10% or smaller. Innovative measurements of the top-quark mass and properties
have also emerged, including the observation of quantum entanglement in the
top-quark sector and tests of lepton-flavour universality using top-quark
decays. Searches for flavour-changing neutral currents in the top-quark sector
have been significantly improved, reaching branching-ratio exclusion limits
ranging from $10^{-3}$ to $10^{-5}$. Many of these analyses have been used to
set limits on Wilson coefficients within the effective field theory framework.
