Been arguing this forever but what is needed are a few 8 hour duration non concentration spells that buff the pet. A few suggestions.If this is some sideways method of creating a spell-less ranger, then just make a spell-less ranger. But don't neuter their ability to use spells just to have a pet. The existing system is better than that.
Pet Insurance- While under the effect of this spell, if your beast companion drops to 0 hp, it drops to 1 instead and is teleported into a pocket dimension until the end of the spell or you use a bonus action to recall it.
Pet Armor - While under the effect of this spell, your beast companion gains a +3 to it's AC and Saving Throws
Hunting Party - While under the effect of this spell, add Hunter's Mark Damage to your beast companion when it deals damage. Your beast companion also has advantage when attacking a creature with your hunter's mark on it.