Not much one can say - updates are a necessary evil (in some respects) !
You are making progress !
I do not make claim to being a sharp tack in a box of sharp tacks, nor to tell gramps how to suck eggs; to me:
sound problem -> module ? what module is loaded into the kernel in a working environment and which when not working ? Black list the offending one, modprobe the working one ? -back to the logs -
chromium; how 'bout this as a suggestion:
Then see if "apt-get" will update/upgrade to the current version ?
sudo apt-get install --reinstall chromium.<whatever_version>
I hope to be of some small help