Not as simple as that when it comes to energy systems. Here’s the example chart of aerobic and anaerobic contributions to the efforts:
As you can see, even 1 min power is a 50% anaerobic and 50% aerobic contribution. Everything longer than 1 min relies heavily on aerobic power. When it comes to anaerobic power there is also a case of muscle fibers (fast twitch and slow twitch). And even fast twitch fibres (the ones that make you go brrrr on your bike) can behave similarly to slow twitch, more aerobic fibres. I believe listening Empiricalcycling podcast about substrate utilisation will help you greatly if you want a real deep dive. Doing sprints during Z2 rides can be beneficial from time to time, and there are some studies that support that - especially when you want to maintain your fitness.
So to conclude in short - you have to train everything with road racing, but you probably will not excel at all of them. There are diesel riders that can ride all day in front of a peloton (“El Tractor”) but they have no sprint at all in them.
In your case, and a case of almost all diesel cyclist (myself included) your fast twitch fibers are untrained (because you do not do any spriting in triathlong) or non existent. For example - my sprint is non-existent - I can barely do 900W when sprinting, that’s only 2x my best 5min power. So town signs sprinting is definitely not for me but give me a longer effort than 1 min and I will do well.