Training suggestions?

I administer our Microsoft 365 admin environment. Everything I’ve learned, I learned on the job. I’d like to do more formal training to round out my knowledge and skill set, but I just don’t know where to begin. I’ve done some research but most of it is through Microsoft’s website. I don’t necessarily need a certification but it would be nice to slowly work towards one.

I guess a good start would be looking into some reputable training sites. Any suggestions?