Others have mentioned an external screen. I have two ThinkVision M14 monitors (selected for USB C power + data on a single cable, and high brightness) and some tablet holders that mount on a range of different 1/4in tripod mounting hardware. Look for tripod clamp stands, gooseneck arms, swivel heads. There's a lot out there, you'll figure out something that works for you. If you want a larger monitor, a VESA mount is what you want. There's various mounting hardware available for this also.
In the interim, try to put a pillow on your lap, and your laptop on the pillow. Try to tense your core a little in general, and especially if you feel discomfort in your back. You'll probably need to maintain the tension for a little while. I find this avoids or alleviates my discomfort- but is probably not a _good_ solution.
For sure it's bad for the laptop, I totally agree, and if you have something better to put your laptop on (a small table that goes over your lap, for example- I believe Ikea sells such a thing) do that. But given the choice between pillow and no pillow, I'd rather damage my laptop than my body.
In the interim, try to put a pillow on your lap, and your laptop on the pillow. Try to tense your core a little in general, and especially if you feel discomfort in your back. You'll probably need to maintain the tension for a little while. I find this avoids or alleviates my discomfort- but is probably not a _good_ solution.