I believe all tooltips were made unselectable since they're supposed to be detail popups, and also should dissappear when your mouse leaves the area. I have no idea the use case for someone needing to manually copy and paste timestamps (and those aren't even formatted with rfc3339) into a document... at that point you might as well use one of the many API clients or curl and parse the data yourself.
Anyways this community isn't an issue tracker, they should open up an issue on lemmy-ui for something like this.
We could def use the help. There's probably a good amount of issues outside of help wanted, that wouldn't be too difficult. Feel free to comment in any of them and we could help you get started.
The new front end lemmy-ui-leptos is also in rust.