I think early Trigger has some great examples of anime as a visual medium - things like Gurren Lagann and Kill La Kill have such a distinct visual style that would be impossible to replicate using live action or CGI. FMA and Frieren could, however, just as easily be in a different visual medium and be more or less the same. And you’re right that the fight scenes in each are fairly forgettable. I think the only one that stands out to me in FMA: Brotherhood is the one towards the end with Wrath. And I say this as someone who has seen a lot of anime - literally hundreds of series.

I saw both FMA and Brotherhood when they were airing. They’re both fine. Just not particularly complex or notable. I dunno what to tell you. I like Princess Tutu and Monster. Those are examples of “not bland” anime.

Frieren is a fine anime, but both it and FMA are wildly overrated. They’re both popular shonen anime with cool action sequences and are both mainstream enough to not be offputting for general audiences. They’re pretty much designed to be popular and accessible, but that degree of accessibility also makes them somewhat bland.

It’s an adaptation of a manga. Specifically an extremely perverse yuri lolicon manga about a girl who is obsessed with magical girls only to become a magical bad guy and wind up forced to fight them. Expect a lot of underage same sex BDSM. Not really something I personally feel comfortable watching.