Is there a way to change the boarder?

[AndOrangutan]

Is there any way that I could change the border style used, I prefer none or solid?

[williamboman]

You can utilize the FileType autocommand for this:

autocmd FileType lsp-installer lua vim.api.nvim_win_set_config(0, { border = "none" })

See :h nvim_win_set_config for which border options there are.