Like you said it really comes down to different styles and uses. Are you an offensive player who hyper pressures or defensive who will wait to create an opening? Knowing the matchup helps change the mindset here as well.

I think this discussion really just amounts to the sad state of ap itemization routes you get on most mages.

Burst: Ludens, horizons, void staff, 3 item wombo

Or.

Defensive / utility: Everfrost, cosmic, zhonyas

pen makes a big difference especially since that 3 item burst will reduce down to around 0 MR on squishies (or close to it). You cant really get this pen unless you build ludens or protobelt. And if they build an MR item like witts you still do decent burst. Meaning, this would be a great way to push an advantage you got early on such as early invade gold or early kill(s) pre 10 mins.

If you go everfrost, you can expect to 1 combo them still until they build (if they build) an mr item. After this point you are a cc nightmare who will want to have your jungler around for deleting them. But by this point, you really shouldnt be alone any how and you will have your abilities up sooner for more rotations in a team fight due to haste from zhonyas and cosmic.

My take is I think ludens may be more beneficial in lower elos because map vision is not quite there yet and you can catch people out more / not be rotated on. If youre winning, keep doing it.