Ok, so I got some feedback from the upstream maintainers (here: https://gitlab.freedesktop.org/plymouth/plymouth/-/merge_requests/340), and the proper fix would be to include this commit: https://gitlab.freedesktop.org/plymouth/plymouth/-/commit/792fe7474a02a1facacdd52e0dcf9053da4b1f6e
I've tested it myself using the current version of Plymouth in testing/unstable (24.004.60-2+b2), and it also solves the problem.
