Can't disable autoformatting

[its-mrarsikk]

I'm using Neovim v0.11.5 on Arch Linux with Prettier. This is my typescript-tools setup:

require("typescript-tools").setup {
    on_attach = function(client)
        client.server_capabilities.documentFormattingProvider = false
        client.server_capabilities.documentRangeFormattingProvider = false
    end,
    handlers = {},
    settings = {
        separate_diagnostic_server = true,
        publish_diagnostic_on = "insert_leave",
        expose_as_code_action = {},
        tsserver_path = nil,
        tsserver_plugins = {},
        tsserver_max_memory = "auto",
        tsserver_format_options = {},
        tsserver_file_preferences = {},
        tsserver_locale = "en",
        complete_function_calls = false,
        include_completions_with_insert_text = true,
        code_lens = "off",
        disable_member_code_lens = true,
        jsx_close_tag = {
            enable = true,
            filetypes = { "javascriptreact", "typescriptreact" },
        }
    },
}

However, vim.lsp.buf.format seems to still use tsserver formatting, as my Prettier settings do not apply. How can I troubleshoot this?
I am aware of #288 and #81, but the fixes mentioned, as seen above, do not work for me, and I wouldn't like to necropost.