I'm not against making things easier. But I feel like it's so easy to over-engineer and rely on proprietary crapware.
Is there a conservative path forward here?
Then again jenkins job can be as simple as "download a repo and run some code in it" without anything fancy so even if SHTF you can migrate away relatively painlessly
The best way I've found is to keep the CI/CD tools as just simple task runners. They should only have to figure out when to run things, inject the necessary environment(and secrets), and figure out dependencies (if applicable) and run those. Whatever they run, you should be able to run the same scripts from your own laptop or a similar.
If the author has already deployed 100-200 times and knows enough to set up a basic build, it would be close to break-even with a fairly wide margin.