Gladiator with versatile combatant

I've been reading that having max block for spells is just as good as having spell suppression, yes or no? Have I wasted points getting up to 100% suppression? Is it better to go full in on one or both?
I do use ancestral vision and 20% chance to avoid ailments. How can I optimize?
No the answer is not fully obvious to me so spare me negative talk please.

Depends what you are doing. Max spell block will prevent more damage taken on average than 100% suppress, but the max damage taken will be higher with block as well, depends on a range of factors.

In terms of going for a mix of both. I do it sometimes, depends how efficiently you can do it and how much defense you need. Layers of defense are good, but they often counter act each other. Example, you wont suppress spell damage on damage that is being blocked. If they do both work together, you don't usually need them both on the same hit, it is the hit that gets through both that you need it on. Lucky spell suppress is pretty useful when using multiple layers I find because of the efficiency, but without 100% you will take some big hits.

Block is king for mapping because you are largely dealing with an extremely high frequency of blockable hits, further scaled by "juicing" the map. In contrast, blocking is largely irrelevant for bossing because GGG purposefully made most lethal boss effects non-blockable. Those same effects can all be suppressed. Having high or capped suppression is a night and day difference in bossing difficulty versus having little or no suppression.

If you mostly or only care about mapping in POE1 endgame, then sure just go max "lucky" attack and spell block cap with gladiator and versatile combatant, which is around 90% and 88% respectively. In this case, having some further defense layers beyond block is useful for not having a yoyo health pool or getting 1 shot. Therefore, keep up endurance charges, get more endurance charges if possible, use determination or sand stance flesh and stone, and have some decent armor from your gear (or evasion converted to armor from iron reflexes node).