I haven't used a lot of different distros, but for me, Debian has been a good balance of those factors. You may need to do more upgrades per decade, but the ones that you do are more liable to go smoothly.
Just my 2¢ on the topic (:
So while debian is a great distribution, with 5y is definitively not in the top 5 of LTS distributions.
It seems to me in the 2020s that 5-7 years is plenty of support for a single OS release, and that OS support teams should be nimble enough to roll out new instances and migrate data at that cadence.
Either the 1-2 hours is a drop in the bucket compared to what you spend on it anyway (like a blog you still regularly update), or you don't actively update the project but still care enough about it to spend half an evening every few years, or you should just admit you don't care about it enough anymore to do even that. In the last case just delete the project.
I want the machine that serves my static blog pages to have, ideally, 0 maintenance.
It needs to do one thing, serve some static HTTP pages and have new pages pushed to it.
Quite frankly I wish some of those "minimal docker first OSs" had taken off.