I don't think there is tbh. It always depends on the context, and users generally want everything at once.

This UX Stack answer is related but doesn't quite answer your question. It contains the guidelines from J. Nielsen but I don't see how they can apply without having a user context. Also, nowadays, who has the patience to wait even close to 10 seconds for something.

A fair amount of the answers are about giving the user good feedback on what's going on, which would have been my answer as well.

A simple load animation is suitable for processes that are short and are unlikely to fail, while a progress bar that actually represents the progress, preferably also telling in text what the status is, is better for longer processes (users should be pretty experienced with loading spinners that keep on spinning even though the page is frozen).

While good system response and clever animations might improve the perceived performance, one should always strive to make one's product as fast as possible. Countless articles treat this subject, for instance this golden oldie from Google.

When your site is running at top speed, there is of course the option to make it slower again if it suits the flow on your site, but the true performance needs to be there.

I don't think there is tbh. It always depends on the context, and users generally want everything at once.

This UX Stack answer is related but doesn't quite answer your question. It contains the guidelines from J. Nielsen but I don't see how they can apply without having a user context. Also, nowadays, who has the patience to wait even close to 10 seconds for something.

A fair amount of the answers are about giving the user good feedback on what's going on, which would have been my answer as well.

A simple load animation is suitable for processes that are short and are unlikely to fail, while a progress bar that actually represents the progress, preferably also telling in text what the status is, is better for longer processes (users should be pretty experienced with loading spinners that keep on spinning even though the page is frozen).

While good system response and clever animations might improve the perceived performance, one should always strive to make one's product as fast as possible. Countless articles treat this subject, for instance this golden oldie from Google.

When your site is running at top speed, there is of course the option to make it slower again if it suits the flow on your site, but the true performance needs to be there.