"Beware of practising your piety before others in order to be seen by them; for then you have no reward from your Father in heaven.
'So whenever you give alms, do not sound a trumpet before you, as the hypocrites do in the synagogues and in the streets, so that they may be praised by others. Truly I tell you, they have received their reward. 3 But when you give alms, do not let your left hand know what your right hand is doing, 4 so that your alms may be done in secret; and your Father who sees in secret will reward you."
Also, the verse you quoted was taken out of context in a huge way. It’s not saying to go around bragging how “bright” you are - that is NOT what letting your light shine means.
An erudite explanation of said verse can be found in the Haydock Bible:
“As when the eyes of the body are pure, and free from the mixture of bad humours, the whole body is lightsome; so if the eyes of the mind, viz. reason, faith and understanding, are not infected with the pestiferous humours of envy, avarice, and other vices, the whole mind will be illuminated by the presence of the Holy Ghost. Take care, therefore, lest by giving way to these vices, the light which is in thee be turned into darkness.”