I kind of just set the bar that “this” is the level of enthusiasm and energy you can expect from me – I’m not a cheerleader.
Improving your social skills is a valid goal. But in the context of a workplace – make sure it’s aligned. Will people listen to you and your guidance on a project? Have you built up enough rapport to delegate or assign work? Etc.
If possible - feel free to go on walks by yourself during breaks or go listen/watch something under a tree nearby but out of sight. Maybe find a coworker or two to go on walks with you.
You don’t have to go 100% social or antisocial - but maybe sprinkling in one or the other could help re-energize.
I typically have on-sites once a quarter and 4 days of meetings and dinners can be quite a swing from my usual remote hermit lifestyle. In addition to sporadic walk breaks between meetings, I will try to duck out an hour or two before we all go out for dinner – my coworkers are pretty understanding that I’m using this time to recharge or run/workout.