Myth check
You must put 是 before 喜欢 because English says “I am like.”
喜欢 is a verb that takes an object. 我是喜欢 is not the beginner default.
Verdict
false
Why
我喜欢茶。我喜欢看书。 The liked thing follows the verb.
English “like” also overlaps 想. 想 is closer to want / intend / miss.
Opinions use 觉得 + a clause: 我觉得很好. That is a different tool.
Better framing
喜欢 + object; 觉得 + clause; skip 是 unless you are identifying a noun.
Practice tip
Replace the object in 我喜欢___ five times (tea, this movie, running, this teacher, spicy food).