Claude Code has essentially fixed this perpetual annoyance for me. Doesn't matter if it's a hacked up deploy.sh that mixes sed, envsubst and god knows what or a non-idiomatic Helm chart that was perpetually on my backlog to fix... today I just say "make this do this thing and also fix any bash bugs along the way" and it just does it. Its effectiveness for these thousand-little-cuts type DevOps tasks is underrated IMO.
Now the actual CI/CD/thing-doers tools that all suck... I'm still stuck with those.