Is this a recent router? If it's 5+ years old, I think this might be one of those situations where it's time to decide to just upgrade our devices and be done with it.
How often do I have to replace stuff that I own?
My car is 25 years old (gasp) and reliable, though not designed for current emissions standards, my laptop is 8 years old and works great, though it can only run so many app-that-is-browser programs, my phone is 4 years old and works, and my router is 5 years old and still kicking, and my table saw is 10 years old and works great.
I'd like to not have to replace my biggest, most expensive tools in my life every couple years, just because someone else has and thinks I should too.
Your 25-year-old car probably emits a lot more harmful substances into the air than recent cars do, so someone could argue that you are actually harming others by continuing to drive it.
Similarly, one could argue that your use of computing devices that only support outdated cryptography is harmful to other people, because it makes it difficult for everyone else to upgrade to more secure algorithms. You might not be directly forcing anyone else to make any particular choice, but your choice contributes to the perpetuation of an insecure ecosystem, just like your car contributes to air pollution in your neighborhood.
I just would like to figure out how to use something for its actual lifetime.
c'est la vie
In the case of routers, using dd-wrt instead of some proprietary firmware that doesn't even do the job properly would be a good start.
If anything, the former opposes the latter.
Luckily with phones the support cycles seem finally to get longer, just like they have gotten with computers.
I'm not sad that my tools from years ago aren't as good as the ones today. That's inevitable. I'm sad that many of them are useful but artificially rendered useless by decisions.
For example, I had no complaints about my phone's battery life, security, or performance in 2011, my phone hasn't changed, and I use it for the same tasks. The same goes for the other items I listed.
My point is that routers don't (for some unknown reason) typically ship with automatic self-updates. The company could just as easily ship a firmware upgrade to fix your SSL issue (why is the burden on you the owner to switch to dd-wrt?) But if that doesn't happen, should the fact that some router companies refuse to upgrade to the latest standard stop us from encrypting the web?
I think no. And I think having to upgrade my router for that cause is an okay tradeoff.
Maybe I have a different standard for a bank then a blog, or a router config page. Or maybe I don't. You don't have to choose for me, not in this case.
I was legitimately curious how old OP's router was in addition to my statement. 5 years is a bit meh, but if you've got a router that doesn't support past 108.11b/g, then it's time to upgrade. Sorry.