Is the truth relative or absolute? Which kind of truth should I go for?

Truth is absolute. In God’s perspective, for example, humans have no right to deny His existence and His signs. God’s view is that all rational and open-hearted humans will believe in Him; it is only arrogance that prevents this belief, as discussed here: A Quranic Phenomenology of Atheism.

However, while truth in itself is absolute (Truth is one of the names of God), our own knowledge and understanding of truth in most cases is only approximate and probabilistic. According to Abū Ḥanīfa faith (imān) is absolute. When a person attains faith, their faith in God is just as “perfect” as an angel’s faith in God. If we accept this, then everything other than faith is approximate. For example our understanding of God’s revelations can only by probabilistic; it continues to improve as way study His words and discusses them and debate about them with others.

Naturally, whenever something can be improved, this suggested that it is not perfect or absolute.

As for what kind of truth you should “go for”, if I understood you correctly, then you should go for God. There is no guidance possible without God. Even if you spend years seeking truth from other sources, even if you read hundreds of great books, you can never attain guidance without God’s help. But if you seek it sincerely and humbly through God, He can give it to you better than anyone else can. So seek God, rely on Him, and realize that there is no truth higher than Him or independent from Him. He created this universe, He created our brains and our rationality. We can never be superior to Him or reach beyond Him.