Can you snap a pic of the 'control panel' and any lettering on its front and or rear? Also the controller label if present/accessible? Someone with more extensive 'historic' knowledge may have some insight.
My personal interest in all things e-bike is only a few years old so your bike predates that quite a bit.. Google suggests a KT-890-led display when searched(ebike display 980)? If your bike has a standard KT controller there may be alternative display options?? - a pic of the controller label will confirm.
But i think you might be looking at a controller/display pair purchase? costing circa £30 for a basic probably as is controller/display upto £100 for the optimum controller upgrade option.
Again a pic of the current controller and space available would help in suggesting alternatives.
If fitted with a throttle (and legal due to age?) your controller may be prone to a hack that enables it to run without a display with throttle control only but testing could brick the controller too.. considering the difficulty finding a 980 ebike display for sale via google a pinout of its wiring connection could be harder , but tbh i scanned quickly and only one page at that..
The hack is to connect the wires to pins #1 and #2 in the display often coloured red carrying the full battery voltage , and blue 'bike lock' to turn on the controller without a display, Though it will work on many ebike controllers? its a risk? and shorting any logic level inputs to your controller to full battery voltage is going to be deadly to the logic circuitry..