Right now on holiday (through Tuesday), but would like learn more. I see your contact info in your profile, if you give consent I'd like send you an email on Wednesday with some followup questions (the first question is "what is the URL for your cloud instance" so I don't want to be asking for it on a public forum)
On my company's cloud instance of Jira, it's a minimum of a 2-3 second delay to do anything. Edit, wait a few seconds, save, wait a few seconds, change a field, wait a few seconds... and God help you if you need to reload the page because something got stuck.
it is more like a general feeling all the time for many of us.
I'm using the latest Firefox on Windows, a developer laptop with 32GB memory that was brand new this spring as well as 500/500 fiber.