I have a load of 32bit laptops, "I'll put ChromiumOS on them", nope, that's not a thing any more. OK, err Linux? Apparently not. Could put Windows 10 on them I guess.
You could try Debian, which is essentially Ubuntu minus some themes. I doubt Debian will drop i386 support soon (I just searched and couldn't find hints of an end of support of i386)
But then you'll have all these kernel bugs.
What do you mean?
Ubuntu is a Linux, but Linux is not only Ubuntu. I have loads of x86 boxes - Debian, Puppy Linux, whatever. (Win10 has a 32-bit option? Whoa. #TIL)
Lubuntu 18.04 (and most other Ubuntu derivatives like Xubuntu etc.) is only supported for 3 years.