I can't comment on the cloud offering, but I agree that the performance and resource consumption of the self hosted Jira is not great either.
To me it is not quite slow enough to negatively offset its usefulness. Perhaps I am also too used to working with even slower web applications to really take note of anything < 1s ;)
Again, to double down on my previous point: where it can get very slow very fast, is for ill configured systems... i.e. when running unnecessary permission checks on very large groups.
Back when I used pine it just loaded instantly! No spinner, no splash screen, no progress bar needed.
And don't give me that "oh but it's in the cloud" crap -- the cloud isn't an excuse to be slow when I have a 300mbps downlink with sub-10ms ping times to headquarters and datacenters of these companies.
Creating a bug report with Jira can be as simple as filling in a summary and a (optional) description, then click submit. If you use issue collectors, you may not even need an account in the system or directly access the Jira application to report the issue.