I'm curious about this part: "The Notes formula language was good ish for the time but really became very dated, and the alternative LotusScript was a dead end too."
IIRC LotusScript was basically VB but with a different object model. Why was it a dead end?
Well I suppose the whole thing was a dead end.
Back then a lot of software particularly in the windows world wasn’t very good at talking to anything else. Today everything talks to everything.
Notes already had so many problems it was sunk and lotuscript which as you say was like script. Good but not enough to stop the titanic hitting the iceberg.