But I'm never at a loss when training in a hotel room, or anywhere. You can always keep fit and healthy. And that boosts cognitive development (or for us less-young types, protects against Alzheimer's). One of the two most important hormones involved is BDNF, which means Brain-Derived Neurotropic Factor. I guess the clue is in the name.
Resistance bands are great for strength training (which gives you a stronger immune system, apparently). I use the Bodylastics brand for the type with handles (you can look on YouTube), which is what I use for upper body work. There are other brands. For squats and deadlifts I prefer the loop type of band (I've several different brands of these). There's a guy on YouTube called James Grage who uses the latter type for everything.
He's a bodybuilder, and I don't follow any of his routines or anything, but he uses the bands with intensity and seriousness (and no barbells or dumbbells at all these days). Others don't take the bands seriously enough. (Yes, do I have a squat rack and free weights in my dojo. But I sometimes travel for extended periods of time, so I'm used to the bands as well.)
Lockdown, smackdown... Keep fit, keep healthy, keep safe.