The first statement “我想陽光燦爛著”maybe means that I am warm-hearted or I have been devoted to the school,the society or the country,so the people around you regard you as pride.you are just like the sun shining around them. It emphasizes the inner good quality of a person.
The second statement seems quite strange. Few Chinese say in this way. The sentence itself has no grammar mistakes,but it gives people a feeling that you haven’t completed your words. We often add something in the sentence. For example,“我現在像太陽一樣熱”to describe you are now pretty hot(physical temperature). What you add express your state and feeling ,which makes the sentence more lively.
Sometimes we only use “像太陽”,but the speaker is not myself but someone else. He says “你就像我的太陽！”. This means he thinks you’re his “hero”. In Chinese, “the sun”also means brightness and the one which leads you to success.