Unless things have changed, then yes. Premium hosting doesn’t have the security system, so API access like Discord should work fine.
That is inaccurate. InfinityFree’s free hosting and iFastNet’s premium hosting, are two completely separate systems with their own features, rules, and functionality. Many of the limitations that apply to free hosting are more lenient or completely gone on premium.
Also, the reason Discord is blocked on free hosting is because of the high rates of people abusing the free hosting infrastructure. It has nothing to do with the personal preference of iFastNet or InfinityFree’s ownership (both companies are for-profit entities after all).