I recommend contributing to open source and learning contemporary web development skills through a platform like freeCodeCamp.org.
Much of this will be review for you. Building the projects will be great projects.
With some practice, you should be able to re-enter the software development job market with confidence.
Remember - the tools may change, but the underlying math and computer science fundamentals haven't changed much. You just need to acquaint yourself with the minority of topics that have changed. You've got this.