Stunlocked Squealer? Inconceivable! The Squealer Gods are not pleased by your report, you clearly are not spamming your punches enough.
Had about 18 TGH back then and never had stunlocking issues even when my shields are down, only thing that could possibly stunlock me would be them god damn Ouka, AFAIK, you cannot be stunlocked out of your FALCON PUNCH animation, so just spam that permanently.