You can simply install the *.debs from
sourceforge, but you will still need to learn, as its dependencies are not typically automatically installed, maybe they will with apt, but I use dpkg directly, so I have to follow that with apt install -f.
Basically, there's no (need for) specific ChromeOS Lazarus, as the Linux version works. Can't really avoid learning if you want to develop anyway.
ChromeOS' Linux subsystem, or to be precise virtual machine (in the name of security by sandboxing, they surely can take the Windows route but no, security is put upfront), is based on Debian stable (currently Bullseye).
Attached is the latest stable Lazarus on my Lenovo Yoga C13 opening one of my old projects.