Retention Bonus

I’m middle management at a Fortune 500 company in the US and we recently had some senior leader changes. Up until now I loved my job and now I’m miserable. Super high workload an my new manager doesn’t seem to like anything the department has been doing. Surprise, surprise everyone is leaving.

I’ve identified an internal role I’d like to accept an offer from but based on things my manager has said, I’m expecting a retention offer to stay in my current role / an attempt to block my transfer.

Any advice on how to proceed? What’s a normal retention offer %? My salary is $250K-$350K depending on bonus. I feel like $50K would be the minimum I’d even consider but would honestly want closer to $100K as I’d need to spend some on additional support around the house. While more money is always nice, this is such a dumpster fire and I don’t even think my manger likes me/the work I do so I’m leaning towards trying to internally move…but apparently I’m the least unliked. I have pretty specialized knowledge in something that makes the company a ton of money and due to some external things the knowledge is especially valuable for the next year or so. It’s still valuable after a year, but there’s an opportunity to really cash in right now. There were two others with similar knowledge but one left the company and the other is on maternity leave for 6 months.

I have some good leverage but really I just want to move internally. Any advice? I’m mainly just nervous they’ll try to block the internal move. I guess if they do that I’ll accept the retention offer and pay it back if I can find something externally.