I don't need to relate to a character to find them interesting and dynamic. The issue with Bojack is that he's BORING and all his friends and family are BORING and the stupid shit they do to each other is TRITE.
ETA: There are a lot of relateable things about Bojack, tbh. He's over the hill, he's stuck in the past, he's struggling to live in a world that has passed him by, his incredibly abusive upbringing lead to habitual feelings of inadequacy and self doubt, he was burdened with expectations from far too young of an age, he hangs out with miserable people who drag him down constantly, he compensates for all of this with an insecure and bloated ego, he's terrified of failure or letting others down.
Bojack is a genuinely interesting character, the issue is that the showrunners can't write for shit and both they and the audience who like the show are too retarded and mollycoddled to see anything deeper than freshman level psychology without getting The Ick.