The amount on the LCA is the minimum they can legally pay you, it's no problem to pay more, you have income tax obligations on the full amount of your pay, of course.
Here are a couple snippets from CFR › Title 20 › Chapter V › Part 655 › Subpart H › Section 655.731 that indicate the LCA amount is a minimum:
(3) Once the prevailing wage rate is established, the H-1B employer
then shall compare this wage with the actual wage rate for the
specific employment in question at the place of employment and must
pay the H-1B nonimmigrant at least the higher of the two wages.
Additionally, they most provide documentation showing that pay is no less than the required wage:
The employer shall also document that the wage rate(s) paid to H-1B nonimmigrant(s) is(are) no less than the required wage rate(s)