Trouble with initial setup on RB750Gr3

In any case, you normally want to use Winbox (as opposed to browser/Webfig).
Without WINE, you are forced to use version 4.x, which while somehow still experimental remains "better" than Webfig, mainly because you can use MAC Winbox connection even if there is not (or it is not properly configured) an IP address, JFYI: