I assume your workplace is using the cloud solution?
Our huge-enterprise in-house install is blazing fast, as long as nobody misconfigures some automation tool to overload the database.
Edit: I did have the bad luck to discover it performs pretty horribly if you’re on a high-latency connection to the office. I think it makes a lot of round-trip requests.
Yes, JIRA Cloud is unusably slow and their "nextgen" rewrite only compounds problems by adding workflows no one asked for and by removing workflows everyone depends on.
Properly configured on-premise installations are usually quite fast.
Edit: I did have the bad luck to discover it performs pretty horribly if you’re on a high-latency connection to the office. I think it makes a lot of round-trip requests.