Le Sigh, during COVID I don't go anywhere. Carrying a monitor is not a problem. But when I traveled, many co-working spaces offer halfway decent monitors for rent. And if you're staying for a while, you can buy one locally and honestly just leave it there when you go. We're talking about $200. It's just part of the cost of being a digital nomad (which you totally make up in many other ways).
Oh, but chairs for me are not a problem. I have been a very happy standing-worker for 13 years now. It started with hip and lower back pain in my early 30s, which seemed f'd up, and then some articles by a Mayo Clinic doctor who worked standing and sometimes on a treadmill. Turns out, it was good advice. Now I stand all day - sometimes 18 hours, and don't even notice. (To be clear, you always move a bit, shift your weight, etc.; it's not being a statue.)
Just like to the other commenter mentioned, be careful of standing all day. My mother was a hairdresser for 50+ years. She needed operations on both her knees.
I think it's all a balance of sitting and standing, and not taking one to the extreme. I say this as I just threw my back out a few weeks ago, because I was sitting all day :( So yeah, I'm not a model person to listen to either!
I have a few small spider veins, but I've had them for 10 years already. And since I work from home, I can play James Brown any time I want. You can imagine I get down; I'm not static.
Slightly more seriously, there is no one answer. But in terms of total human history, sitting isn't something we spent a lot of time doing. Sleeping, lying flat, we obviously spend about 1/4 to 1/3 of our time doing. Standing or walking or running surely must be a big portion of the rest. Sitting would only be reserved for when you have the time to "do nothing". That's kind of a new concept. Thusly, I'm not afraid.
For a 50 year old nerd who hasn't exercised in a year, I'm still well above the health and capabilities of a lot of same age people. And when I'm in a good environment with outdoor play areas (mountain biking) or indoor gyms, I'm fit. Aesthetically, losing hair and gaining less elastic skin is much more a concern to me than some tiny purple lines in my ankles or knees :/
While it's not a big 4K monitor, when I used to travel a lot pre-COVID, I got a 15" USB monitor for my laptop. It was small enough to easily haul around in a carryon bag and gave some useful screen real estate.
I bought a 15" 4k UPERFECT portable gaming monitor for this situation. It's about the size of my 15" MBP, only thicker. I was worried about it being sketchy (as far as I can tell, they only sell on Amazon), but aside from difficulties syncing sometimes if I turn on the monitor before the computer and it decides there isn't a signal, it works great.
Oh, but chairs for me are not a problem. I have been a very happy standing-worker for 13 years now. It started with hip and lower back pain in my early 30s, which seemed f'd up, and then some articles by a Mayo Clinic doctor who worked standing and sometimes on a treadmill. Turns out, it was good advice. Now I stand all day - sometimes 18 hours, and don't even notice. (To be clear, you always move a bit, shift your weight, etc.; it's not being a statue.)