Battery issue - or suspect more?

Away from home.  No WR service manual, no multimeter.  Suggestions and ideas for what I should be looking at beyond battery voltages?  The issue:

1. This is a 2008; I'm the original owner from 2008, no engine/electrical mods other than attaching the battery tender pigtale back in 2008.
   
   
2. Battery is about three years old, light to no use last year due to life issues.  Battery is hooked to motorcycle battery tender throughout winter and periods of light/no use.
   
   
3. Put the bike back on the road about a month ago when the weather got better.  Started first crank after the winter; no issues (but it had just come off 7 months of battery on battery tender).  Have been doing a few short rides over the last month.  No starting issues, no error codes
   
   
4. Two days ago, went to start the bike in the morning, almost caught and then the battery was dead.  Onto the battery tender while I went to work in the truck.  Fired up fine yesterday, rode back and forth to work.  No issues, no error codes.
   
   
5. One unusual thing - the instrument panel clock was reading some weird time not remotely close to the real time.  The time had been accurate the day before  But no issues otherwise - no error codes.
   
   
6. Started fine again this morning, rode to work; turned the bike off for a moment at work after arrival - and bike wouldn't even crank close enough to manage a start.  Now it's back on the battery tender - it's about a 19 mile ride each time back and forth to work.  (am I seeing a charge only gives me about 60 miles of running time?)
   
   
7. Haven't done the factory recall on the stator yet - nearest dealer is a distance away and I've never done the planning to get that done.
   
   
8. With the clock weirdness and short distance I'm riding, I suspect I should be checking more than whether the battery has finally run out of life?
   

The instrument panel clock has not shit the bed any time in the last 12 years of riding - all else on the instrument panel seems to be normal, including no error codes.

BTW, as a maintenance, service abject novice, can meaningful multimeter readings be taken from the battery tender lead I have run from connection at battery terminals to tank bag for charging cellphone, GPS batteries?  The lead is attached to battery terminals, so am I essentially reading what I would be at the terminals the lead is attached to?

If nothing else, I guess it's time to schedule that stator recall replacement when I get home after Wuhan Virus House Arrest Madness.  Never did get a letter from Yamaha or the dealer as the original owner... wouldn't even know about it if I hadn't read about it here.

BTW, any suggestions on a RELIABLE alternative to the stock Yuasa YTZ7S?

Amazon Prime will have a new Yuasa here in a couple of days - for $129.
https://www.amazon.com/Yuasa-YTZ7S-BATTERY/dp/B002OQASG4

Now that I'm at the back end of my 60's, my old riding partners have called it a career and I do a lot of my back road gravel tourist stuff alone these. I ride with a SPOT and the gear to spend a night or two broken down awaiting help/walking out - but being broke down due to a dead battery is something I'd like to minimize the possibilities of.

Never done any "what's the most reliable battery" shopping up to this point.

I've had great luck with these - https://www.amazon.com/FirePower-Featherweight-Lithium-Battery-HJTZ5S-FP-IL/dp/B00DX894B2/ref=sr_1_2?dchild=1&keywords=FirePower+Featherweight+Lithium+Battery+HJTZ5S-FP-IL&qid=1591284898&s=automotive&sr=1-2

No need for a battery tender either due to super low self discharge, needed every 3 mo. of no use.