I also tried https://github.com/smoka7/multicursors.nvim and the experience was horrible. Then I tried https://github.com/brenton-leighton/multiple-cursors.nvim and I absolutely love it. It has conflict with cmp, but the README has great tutorial on disabling cmp only when using multiple cursors, and dealing with other plugins to maks them work or disable them in the multicursor mode.
I get that, but OP clearly put a lot of effort into this in a good faith, made it open source, and now when he posts it here, he gets downvoted without any comment (as of when I wrote mine) with reasoning behind it.
Plasma has a setting to synchronize selection and clipboard or something like that.