I want to provide a quick update for this topic. The work is still in progress to ship this feature, Ability to link to a specific comment "Permalink", and aiming to roll it out in the next couple of weeks and it will include all the existing functionality that was on the old issue view. I know this has taken a while to build out, but rebuilding Jira issues is no small feat, so we very much appreciate your patience on this.
In the meantime, you can opt out of this new issue experience via your Personal Settings > Jira Labs section will have a 'new issue view' toggle to turn it on or off. We will not be disabling this opt-out option until we have rebuilt all the key features of the Jira issues experience you have come to know and love.