MDS_STORES

"MDS" is part of Apple's Spotlight indexing feature. It is a known issue that the system logs are flooded with these messages and some well respected forum contributors have confirmed that it occurs with a clean install of macOS (no third party apps, or restore from backup). Unless you actually receive a log entry that mentions some of those "MDS" entries could not be saved because there were too many, then the only thing you can do is ignore them. Of course you can try contacting Apple Support directly and try to escalate the issue to an engineer, but you will spends lots of time and may not be successful.

You can also provide Apple with product feedback here (Apple will not respond):

You can also try contacting Apple corporate (Apple may respond):

To look for possible software issues run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper. If you give EtreCheck "Full Disk Access", then the report will include extra information that may provide additional clues.

FYI, normally the system logs are completely worthless for troubleshooting any macOS issues because the logs are flooded by cryptic, sanitized messages that usually appear to be programmer's debugging logs still left enabled on the released product. The only useful log these days are Kernel Panic logs and many of them can only be accessed from the Finder because the Console app actually won't display all the logs anymore (yes, that is what Apple thinks of the logs). At this point Apple should just disable system logging on released products.

I don't understand as to why I was told that MDS_STORES was a Google Chrome issue though.

Apple employees are human; they make mistakes. Some were still in pre-school when Spotlight was introduced. Ref: Spotlight (software) - Wikipedia

You can "corral" some of Spotlight's hunger by using its system preferences:

Change Spotlight preferences on Mac - Apple Support

There is no need to have Spotlight index all the thing its default setting determine. I never have it do my Mail app because I have a lot of retained mail and can easily search it from within Mail. Backup drives like Time Machine will bog down things if you let it Spotlight search it. Same with Fonts, Apps, Bookmarks, Contacts, etc.

My Search results choices are quite limited yet give me what my workflow needs:

This actually falls outside of the realm of knowledge for most Apple agents & techs so it is not surprising.

I suggest you run EtreCheck as I suggested earlier so we can see if perhaps your performance issues may be due to some other hardware or software issue since most Macs have their logs flooded with the MDS entries.