Same thing goes here. It works great until it doesn't. E.g. we went with that route with GH Actions, until our tests didn't fit into the memory of the provided

Same thing goes here. It works great until it doesn't. E.g. we went with that route with GH Actions, until our tests didn't fit into the memory of the provided machine sizes anymore (shouldn't be a problem anymore as GH provides options for bigger runners now). So we had to spend 1-2 days on setting up a self-hosted runner in a way that it wouldn't be too heavy in maintenance, and then probably another 1-2 days of rework over the next few weeks to iron out the kinks.