  Cosmic birefringence is a parity-violating effect that might have rotated the
plane of linearly polarized light of the cosmic microwave background (CMB) by
an angle $\beta$ since its emission. This has recently been measured to be
non-zero at a statistical significance of $3.6\sigma$ in the official Planck
PR4 and 9-year WMAP data. In this work, we constrain $\beta$ using the
reprocessed BeyondPlanck LFI and Cosmoglobe DR1 WMAP polarization maps. These
novel maps have both lower systematic residuals and a more complete error
description than the corresponding official products. Foreground $EB$
correlations could bias measurements of $\beta$, and while thermal dust $EB$
emission has been argued to be statistically non-zero, no evidence for
synchrotron $EB$ power has been reported. Unlike the dust-dominated Planck HFI
maps, the majority of the LFI and WMAP polarization maps are instead dominated
by synchrotron emission. Simultaneously constraining $\beta$ and the
polarization miscalibration angle, $\alpha$, of each channel, we find a
best-fit value of $\beta=0.35^{\circ}\pm0.70^{\circ}$ with LFI and WMAP data
only. When including the Planck HFI PR4 maps, but fitting $\beta$ separately
for dust-dominated, $\beta_{>70\,\mathrm{GHz}}$, and synchrotron-dominated
channels, $\beta_{\leq 70\,\mathrm{GHz}}$, we find $\beta_{\leq
70\,\mathrm{GHz}}=0.53^{\circ}\pm0.28^\circ$. This differs from zero with a
statistical significance of $1.9\sigma$, and the main contribution to this
value comes from the LFI 70 GHz channel. While the statistical significances of
these results are low on their own, the measurement derived from the LFI and
WMAP synchrotron-dominated maps agrees with the previously reported
HFI-dominated constraints, despite the very different astrophysical and
instrumental systematics involved in all these experiments.
