you are pretty much correct, except buying a used fourstroke, especially a 250 and especially an early model is bad. it won’t be long before your dumping a grand or more in it to redo the topend. a newer model won’t be as bad since they improve the reliability and wear and tear on the valves and etc each year. the 250 are runner harder so obviously more wear.
buy a new 250 fourstroke or a used 2stroke 250