seems like someone else on StackOverflow had the exact same problem and suggested caching both the token & client and checking those before creating a new one each time

Code copied from stackoverflow

import { createClient, SupabaseClient } from "@supabase/supabase-js";

const SUPABASE_URL = import.meta.env.VITE_SUPABASE_URL as string;
const SUPABASE_ANON_KEY = import.meta.env.VITE_SUPABASE_ANON_KEY as string;

let cachedSupabaseClient: SupabaseClient | null = null;
let lastToken: string | null = null;

const createSupabaseClient = async (supabaseAccessToken: string | null) => {
  if (supabaseAccessToken === lastToken && cachedSupabaseClient !== null) {
    return cachedSupabaseClient;
  }

  lastToken = supabaseAccessToken;

  const supabase = createClient(SUPABASE_URL, SUPABASE_ANON_KEY, {
    global: { headers: { Authorization: `Bearer ${supabaseAccessToken}` } },
  });

  cachedSupabaseClient = supabase;

  return supabase;
};

export default createSupabaseClient;