Tails is always going to be second fiddle to Sonic, that's literally the basis of his entire character. Anytime he's not with Sonic it's such an implicit consistency error that you've essentially created an alternate version of what he's supposed to be.
Look at Miles and Nine, these characters are their own separate versions of Tails because they explicitly go against his own character's design motivation.
If you cannot handle the fact that Tails is always going to be Sonic's "cock sleeve" then you didn't like the character as he is from the beginning.
>But what if they grew the characters?
This has literally never happened even once in the entire franchise. SEGA has now even stepped away from identify classic Sonic as "younger Sonic" because they clearly do not like to depict actual time passage in the IP. Things like this could only happen in fanworks and fan designs and that's, again, essentially making a different AU entirely just to establish new characters that are alternate versions of the actual characters.
You don't like Sonic or his cast for what they are. You just like the idea you have of them in your head.