Just to follow up, my attempts to get vimtex to work unfortunately were unsuccessful. However, along the way reading neovim plugin docs I started to figure out the difference between neovim and vim and was able to get things working via the following process:

sudo dnf install neovim

sudo dnf install python3-neovim

mkdir -p ~/.config/pack/foo/opt/mytex

cd ~/.config/pack/foo/opt/mytex

[download https://github.com/peterbjorgensen/sved/ftplugin]

cp ~/.vimrc ~/.config/nvim/init.vim

add the line "packadd mytex" to init.vim

add the line "alias vim='nvim'" to ~/.bashrc :)