Yep.
Using a bonus action to cast a spell (regardless if it’s your own spell or a magic item allows you to cast it) means the only other spells you can cast that turn are cantrips with a casting time of 1 action. (PHB, Ch 10, Casting Time) #WotCStaff
— Dan Dillon (@Dan_Dillon_1) June 30, 2019
If i cast as spell as bonus action using the Tome of the Stilled Tongue the only spell I can cast are cantrips?
