I honestly dont undestand all the bad reviews on this one, definetely overhated.
It does have some cringy lines and weak dialogue but its overall a more than decent musical. Theres no song in partiuclar that drove me crazy but the choreography, script and production are good.
It is an almost sung-through musical, so keep that in mind in case you expected some scattered songs throught.
Regarding veracity, i have no idea tbh. I couldnt care less about the royal family of the UK so it might have not been 100% historically accurate and i probably woulndt have noticed. For my basic knowledge, it covered it all but i couldnt testify to it being perfect in that area.
Overall an entertaining musical that doesnt particularly bring anything new to the table but its more than an acceptable addition.
If you are not a fan of musicals, this wont be the one that makes you like them, so maybe just skip it.
If you usually enjoy musicals, give it a chance!!