Shutters. And spares.
There are some other good answers, but we're talking about invincibility here, which is why, starting with my answer to the previous question, I'm feeling pessimistic.
Particularly, I'm feeling like your threat envelope may include such drastic measures as detonating a nuke (and I don't mean any puny "tactical" nukes, either) right in your soldier's face. In other words, protection against projectiles is great and all, but if being hit with a ship-killer laser results in a mission kill, we're not there yet.
So... I present to you, shutters and spares.
As other answers have already mentioned, your first line of defense is going to be making the holes by which your sensors (cameras?) "see" as small as possible. The next step is to design a system that allows you to slam a cover ("shutter") over the sensors as quickly as possible when you detect an attack with the potential to damage the sensor. If you can do this before the attack hits, even better, but since the attack you're mostly worried about involves large amounts of radiation, your first warning may be the sudden thermal spike as your sensor turns into disassociated ions. At that point, you're mostly engaged in damage control and hoping you don't get so much bleed-through that it fries the computers inside the suit.
That's where spares come into play. Hopefully you aren't facing an enemy that can dish out such attacks with impunity (or else you're probable hosed). Your design goal is for the user inside the armor to be able to replace the cameras when they get fried. (Tip: this may be easier if they tend to get vaporized.) Be sure to do this while the outside protective cover is closed. You'll still be blind, but it won't be an instant mission kill.
Oh, and since unobtanium is perfectly reflective, you could also employ retroreflectors surrounding the sensor apetures, as suggested by DKNguyen (thanks!). This won't do much against bombs, and an enemy firing from orbit might be able to get out of the way of the reflection in time, but it may cause any nearby attackers to think twice.
(Overkill? Maybe, but the OP did say invincible; my goal is literally something that can walk through a point blank nuclear blast and remain Combat Effective 😁.)