  We present a much shorter and streamlined proof of an improved version of the
results previously given in [A. Posilicano: On the Self-Adjointness of
$H+A^{*}+A$, Math. Phys. Anal. Geom. (2020)] concerning the self-adjoint
realizations of formal QFT-like Hamiltonians of the kind $H+A^{*}+A$, where $H$
and $A$ play the role of the free field Hamiltonian and of the annihilation
operator respectively. We give explicit representations of the resolvent and of
the self-adjointness domain; the consequent Krein-type resolvent formula leads
to a characterization of these self-adjoint realizations as limit (with respect
to convergence in norm resolvent sense) of cutoff Hamiltonians of the kind
$H+A^{*}_{n}+A_{n}-E_{n}$, the bounded operator $E_{n}$ playing the role of a
renormalizing counter term.
