Animal Companions: Beastmaster errors?

[Falco271]

One of the drawbacks of a ranger is that the progression is slow. Or at least, slower than Druid/Beastmaster.

So, take the ranger AC (which gives you the edge advantage), take Beastmaster @2nd, and immediately have 2 AC (choose which one to use) plus the following advantage when taking the beastmaster feats:

Beastmaster.

Mature Beastmaster Companion:
All of your animal companions grow up, becoming mature animal companions and gaining additional capabilities. During an encounter, even if you don't use the Command an Animal action, your animal companion can still use 1 action on your turn to either Stride or Strike.

And later on:
Specialized Beastmaster Companion
Your nimble and savage animal companions become cunning enough to become specialized. Each companion gains one specialization of your choice (choose separately).

Special You can select this feat more than once. Each time, add a different specialization to your nimble and savage companions. Your nimble and savage companions can have up to three specializations each.

A ranger companion normally can get only one.

[HumbleGamer]

It's ok imo.

The beastmaster is the archetype which deeply specializes in companions.
And in order to have 3 specializations you have to forgo.

lvl 14 feat
lvl 16 feat
lvl 18 feat ( this third one "could" be avoided, since there are just 2 useful specializations for what concerns dex/str builds ).