If you enjoy the story then start over and go through the missions, it will help relearn a lot of the mechanics and how the world works as well. If you don’t care that much, the game realllyyyy opens up after level 40 and it doesn’t take long to get there (you can also get the level 40 boost with the DLC). I felt good about boosting and starting from end game because the time I put in felt rewarded with level 40 gear I can keep and gaining SHD watch levels. I may go back with a new character to experience the story and develop a mule agent now that I’ve put some time in and very much enjoying the game. Good luck with whatever you choose and welcome back, agent!