Is a creature’s Innate Spellcasting save DC affected by changing ability scores or adding Spellcasting features from another creature?

I’m creating a Svirfneblin Evil Mage by combining the stat blocks for each Evil Mage and Svirfneblin.

A Svirfneblin’s Innate Spellcasting Save DC is 11 and its INT is +1. An Evil Mage’s Spellcasting Save DC is 13 and its INT is +3.

I’m taking the abilities from Evil Mage and Svirfneblin and taking the higher ability scores (and modifiers), does the increased INT modifier from the Evil Mage’s score affect the Innate Spellcasting spell save DC?