Nick Schade Kayak Stroke Simulator

[JohnAbercrombie]

If you can, then I'm fine declaring whatever you're doing as "good enough!"

Certainly; there's no point in excessive self-criticism.

But...I think it's important not to confuse strength/fitness/(relative) youth with technique.
It is possible to improve our paddling technique - at least a bit - even after years of bad habits.
As the years roll on, it's much more difficult to improve our strength and fitness.
And waiting until our physical decline is apparent before trying to develop efficient paddling technique is probably not the easiest path to follow, IMO.
Also, for some paddlers, analyzing and optimizing our paddle stroke is an interesting activity in itself.

 

[JohnAbercrombie]

at least a couple hours

I'm sure you could go much longer with short pauses, etc..
And, you are covering in 2 hours what would take most average paddlers close to 3.
Even in my geriatric paddling group, being able to put in a 12-15 nautical mile day and have enough 'left in the tank' to deal with a major problem (adverse current, weather change, surf landing, rescue or tow) and then set up camp and take care or oneself is the minimum expected of participants on most trips.
You are younger and a lot stronger than the people I hang out with - you should aim at a higher benchmark!
Paddlers like Yota Kano and Martin Rother can put in day after day of 40+ miles , camping at night. Martin Rother mentioned in a R2AK podcast that he paddled from Vancouver to Comox as a training paddle to visit a friend!

 

[JohnAbercrombie]

When the legendary cellist Pablo Casals was asked in his later years (80s) why he continued to practice the cello for hours every day, he answered: “Because I think I am making progress.”