You can middle click page links in LK to open that link in a new tab. However after the update to 0.19, middle clicking stopped working for the "Go To Page" button in side popouts. Furthermore, it has never been possible to middle click a linked page on a board, or to middle click your pinned pages at the top of your page tree on the left.

Anything that can be clicked to navigate to a new page or create a sidebar popout, should also have the function to open that link in a new tab with middle click.

Link to Discord discussion that spawned this suggestion: https://discord.com/channels/491043257661390848/579765936391847943/1520565549766283306