> I'm never getting into another startup which has financial risk like that without being a core expert in that risk/tech
This may be something that is 'unstated', but unless you actually had access to fix something that was wrong, as well, being an expert in that wouldn't really help all that much. I've been in situations where I have explicit/expert knowledge of XYZ, but when the people responsible for XYZ do not take your input, and/or don't provide you the ability to fix a problem, expert knowledge is useless (or worse, it's like having to watch a train wreck happen when you know you could have stopped it).
This may be something that is 'unstated', but unless you actually had access to fix something that was wrong, as well, being an expert in that wouldn't really help all that much. I've been in situations where I have explicit/expert knowledge of XYZ, but when the people responsible for XYZ do not take your input, and/or don't provide you the ability to fix a problem, expert knowledge is useless (or worse, it's like having to watch a train wreck happen when you know you could have stopped it).