The only thing I ever did with my laptops when it wasn't plugged into a docking station at a desk was surf the web, and I can do that from my phone.
I can't work in bed for hours. But I can for a half hour after lunch, take a nap, then set back up at the desk as I am now.
I lived without a monitor for several years, you get the hang of it. I did have to bump up from 13" to 16" so I can use it without reading glasses for a few more years.
I'm definitely more efficient with more real estate, but not in a way that holds me back most of the time.
I've also trained myself to type on a laptop in a way that's hard to describe but: left hand V to Q, right hand N to P/[, so at a natural angle for my wrists. I've been using a split keyboard for long enough that twisting my wrists to accommodate a narrow keyboard isn't something I was willing to keep doing. This lets me get paragraphs/pages written without pain, whether I'm at the desk or not.
Airplanes, coffee shops, recliners, internetless cabins... a laptop's been all I needed for doing everything from web development to audio synthesis algorithm development.
I have a nice desktop setup, 5k2k, keeb, trackball, stream deck, my laptop runs it without making any noise, slowing down, or otherwise misbehaving.
I can easily drive to the manufacturer's authorized retail outlet in the event that it has problems, which has indeed happened twice over the nine laptops I've owned from this manufacturer in the last 15 years.
YMMV. Brand not mentioned out of respect for the aesthetics of this thread.