I'd be getting a bigger m.2 drive myself, but 120GB is doable, you just have to tweak system settings and manage the space more carefully.
we have plenty of laptops at work with 120GB SSD's that work fine.
things like changing the system and user environment variable for TMP and TEMP locations to the HDD, turning off hibernation, moving the pagefile to the HDD, and when installing, change C:\program files\ to, say, D:\program files - that sort of thing.
programs you use a lot, like Office, keep those on C:\, but things like VLC, Adobe, 7Zip, browser cache, iTunes, etc - put all them on the HDD.
we have plenty of laptops at work with 120GB SSD's that work fine.
things like changing the system and user environment variable for TMP and TEMP locations to the HDD, turning off hibernation, moving the pagefile to the HDD, and when installing, change C:\program files\ to, say, D:\program files - that sort of thing.
programs you use a lot, like Office, keep those on C:\, but things like VLC, Adobe, 7Zip, browser cache, iTunes, etc - put all them on the HDD.