I also recommend having a second set of all your essentials that you can keep packed in a case all the time - chargers, hairbrush, hairdryer (hotel ones are usually awful), toiletries / first aid bag (especially if you’re not flying and don’t have to worry about liquids), nail clippers/scissors and file, tweezers, little sewing kit to mend buttons etc., cutlery for takeaways, travel cup etc.
exercise - try and keep some sort of activity in your routine, hotel gym or pool if that’s an option, take shoes that are good for gym / a walk rather than just smart work shoes, I usually have a set of resistance bands in the suitcase in case there’s no gym
sleep - spend some time working out what helps you sleep in new places, for me I bring a silk pillowcase from home for my top pillow, eye mask and ear plugs, comfy sleep clothes that I won’t be embarrassed about going out in a fire alarm in - leggings and a t shirt for me or shorts in hot weather.
entertainment - kindle rather than books if you like reading, a small Bluetooth speaker if you like music, I tend to not both trying to get hotel TVs to work unless they’re smart with built in streaming, so a laptop with decent speakers is good for watching TV / films.
Food - eat some vegetables! I know that sounds crazy but when I first started travelling for work lots and eating out, I realised I ate far too little fruit / veg because the portions that come with most meals in restaurants etc. just aren’t big enough. I make sure to order a couple of vegetable sides usually - although I guess it will depend a bit on your expense account situation. Take some decent coffee, especially if you’re going rural / away from coffee shops. I use coffee bags now after an incident trying to clean a cafetière in a hotel bathroom sink. I take a travel kettle too because most hotel kettles are disgusting.
cleanliness - I know they should be clean, but it can be variable. I usually have a pack of antibac wipes I can use on the major touch points - taps, light switches, bedside table. Have slippers you can put on rather than bare feet, and shower slippers / sliders in case the bathroom is a bit grim.