> I use an 11-year-old machine

What OS are you running that can't run modern versions of browsers, and on what hardware?

Current Chrome runs on Windows 10, which came out 9.5 years ago but was intended to run on older computers, and macOS Monterey, which runs on Macs from ~2014-2015 depending on the model. But even Big Sur before that, the most recent version of Chrome which runs on that is Chrome 138 from just 6 months ago, and that doesn't seem old enough that you need to build userscript hacks.

I'm really curious what you're actually running. Generally speaking, an 11-year-old desktop should be able to run the current browser, and if not, a very recent one.