Generally, it takes 1-2years to learn and to get grip on UI/UX design If you're looking for a faster, more flexible alternative, then you might consider a UX design course. Many institutions offer certifications that can help your resume stand out. I personally recommend you to choose the Intellipaat UI UX design course which helps you to become proficient in this field and also provides certification which is globally recognized it has great value in the market.
Before that do check out this UI/ UX free course video from Intellipaat