With the amount of fuck-ups from Microsoft, this might not be necessary, but:
The average user doesn't want to install the operating system or doesn't care about it as long as they can do their things, and those who care can easily do so today. Thus, IMO, advertising to the end user is a waste of resources.
Focus on permeating it in governments, institutions, and OEMs to increase market share and break the "Linux is complicated / incompatible / for developers" stigma, then organic adoption out of these environments will grow - at least among people who can actually use it with the supported software.
Really, this seems to be the best way to spread Linux adoption to me. I would bet that Linux got at least a good few users from the Steam Deck coming with it pre-installed. Big way to show people that for most things the average user doesn't need to go into the command line to use their system for what they need as well. Of course, continued improvement in the software included in the most popular distros would really boost Linux adoption as well. I've seen plenty of people say they'd make the switch - if only they could use MS Office or Adobe software on it. Alternatives like LibreOffice, Thunderbird, Kdenlive and the GIMP have come a LONG way since I first made the switch around 2009, but especially the Adobe software still outclasses the competition when it comes to features. MS Office isn't as hard to let go of, especially since you can still use Office 365 Online on Linux and LibreOffice is closer to having all the OOTB features of MS Office than the other programs are to Adobe, but you have to convince people to give it a try first and a lot of employers still require MS Office for work.
I will also say, though, that it was only due to Windows Vista otherwise bricking my laptop back then that I even made the switch. I'd heard of this mysterious OS named Ubuntu so I thought I'd give it a try to save my laptop before I bought a new one, especially since I was living abroad at the time and didn't want to deal with the hassle of buying a computer with a foreign language version of Windows on it. So I had a friend burn me a copy of Ubuntu 8.10, it worked like a charm, and I only ever since ran Windows at home when dual-booting for a couple years for gaming purposes before Proton became a thing. I didn't even know Ubuntu was Linux until I'd installed it and started learning how to use it in earnest. Really showed me how even then Linux wasn't so difficult to use for the average computer user.
The thing is, without a unified GUI it's impossible to get an answer to "how to X on Linux" that doesn't involve the CLI (and that'll work for everyone). Even the ones that do are often distro-dependent.
People can still get things done by searching for "how to X on <distro> using the GUI".
Your partially missing the point. Linux is unlikely to be something someone who doesn't like computers is going to use. It is something people who are power users and computer lovers will use. Its stolen the market share from the old school windows power users.