Woo Bulkaction very slow and Gateway Time-out

When bulk editing products in Woocommerce, no matter it’s a product, orders or pages, etc. It’s always very slow and ends up with a 504 Gateway Time-out about 30 seconds after.

However, despite the displayed error message, the editing process continued in the backend which you can find it’s continuing executing command if you refresh the product list or by looking at the real-time CPU usage.

The problem is, it’s not normal that the woocommerence are unsurprising slow, even editing 20-30 products could also lead to a 504 timeout error.

I have upgraded the instance to AWS t3.medium and moved the database to RDS, my database is less than 1 GB and the WordPress is slow even there is no traffic around. Therefore I don’t think there is a hardware limitation but correct me if I am wrong.

Is it normal that woocommerence is this slow? If so, how can I extend the “504 Gateway Time-out” timeout limit, so the error won’t appear again during executing large tasks?