+1 on this.
We have also faced this issue (500 with timeout) while polling a bulk querying status. Our query fetches a bunch of data for each product (images, variants, inventory items, inventory levels) and my understanding is that either reducing the amount of data we ask for or ask for less products at a time is a reasonable workaround. However, I do think that it would help (us and our customers) a lot if this gets fixed on the Shopify side.