I often hear these mistakes made by German speakers who are learning English.
They say: Trainings.
The problem here is the plural form. It sounds very strange to use a plural form of this word.
Correction: Training courses.
E.g. I attended several training courses at the start of my new job last year.
As an alternative we could use training events.
E.g. He organises all the training events for our department.
A further alternative could be training sessions.
E.g. There are 6 training sessions in total. Each session lasts 3 hours.
Have fun learning English!
Louise