Ai is intransparent to nearly everyone, and as such should not be used for voting or similar.
Blockchain is a way to ensure no one can tamper with the history of some data undetected, which might be used for keeping a count of the votes, but for most normal people it is also intransparent, so it should only be used with caution if simpler methods are not an option.
I never heard of DAOs before, but seeing the start of the wikipedia entry, it looks like an interesting way to use technology. But it suffers the same problem as the two other technologies: it is intransparent for a lot of people. Also if there is a bug in the software (which will happen at some point in time), it will be hard to fix it.
You have a Thinkpad? As far as i have heard their linux compatibility is fairly good. An yes, ubuntu won’t have more problems than windows with low power devices. My old 4GB ram, 1.4GHz 4 core laptop ran linux mint fine.
Ps: linux mint is a ubuntu fork, and has a desktop interface that looks a lot like windows (example: in the bottom left there is the linux mint logo that you can click to open the start menu like on win 7).