Your wording is hard to understand. Are you asking if you can make /usr its own partition? If that’s your question, you can. You need to make sure that “usr” and “fsck” are in HOOKS in /etc/mkinitcpio.conf.
I can see how /usr can balloon in size. My /usr is 22G with 1613 packages installed.
My experience was Slackware in 1993. Some kid in another dorm was running it on his computer and he gave me an account on it. I’d dial into the University network and telnet to his server to mess around. I believe the kernel was 0.9x something.
Over the years I’d used Linux in various forms: built a router using Linux at a job, installed Slackware on my desktop at home using floppy disks, ran Redhat on most of our infrastructure (web, samba, ftp, sendmail, openvpn, …) at another job, run Arch Linux on my desktop at home along with Debian in my home lab.