Not OP, but it looks like they are using texlab for completion: https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md#texlab
Apart from that there is https://github.com/lervag/vimtex with file type support, document compilation, etc. For grammar checking I use https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md#ltex and for snippets https://github.com/L3MON4D3/LuaSnip. See https://github.com/iurimateus/luasnip-latex-snippets.nvim for latex snippets and what you can do with them.
The vaccine does not stop covid, it does not make you immune, it does not stop you from spreading covid and you will have to get another dose after about 3 months. And then there are possible adverse effects like myocarditis, especially for young men. All this should be considered.
There are other ways to strengthen your immune system. They should be considered too. Most people that have died due to covid have been severely ill, morbidly obese or very old. Eating healthy, getting enough exercise and making sure Vitamin D levels are sufficient will make covid much less dangerous. I much prefer that to constantly getting new boosters.