If it's the computer of an older family member or something, just put Firefox and ubo on their system for them and be done with it. They will use whatever software is preloaded, and being shown how to use it is a much lower barrier to entry than the cognitive load of finding, vetting, installing, and configuring new software.

I used to try to patiently explain why people should do xyz. Now I explain to people why I'm going to change xyz on their device, and if they don't slam the breaks I just do what needs to be done right then. If someone doesn't know what an adblocker is they are getting one so they can see for themselves and reflect on what companies have been putting them through for years to make some incremental amount of money.