Cap'n Kobold
Hero
I would remove the "animal" flavour of the class and make it a purely mechanical companion class.So who wants to work on an "animal companion class" side project? It feels like you could do some cool things with that idea.
The base class could be mostly "pet", while ranger and/or a feat could upgrade it to "combatant". Give it a few abilities as it levels up, and provide it decent stat progression instead of basing it on the Monster Manual. Maybe draw on some of the ideas of the reworked summon spells from Tasha's.
Then you would have subclasses where the flavour resides, whether that is companion animal, artificial construct, ancestral or Nature spirit, animated dead, faithful mount, extradimensional monster etc.
The base class would cover pet mechanics and a choice of pet templates for different purposes, alongside additional choices like Warlock invocations. The subclasses would modify the companion slightly (giving it the beast, or construct, or undead etc type) as well as granting the character some abilities. The subclass with the Beast companion would get some druidic and wilderness abilities, others might get necromancer, or artificer-like abilities etc.