Since @ndarilek is using ElixirLS Fork they should look at Issues · elixir-lsp/elixir-ls · GitHub instead.
I’d expect the first one to work. Does it work if you start the whole line over?
Can you explain what you mean by the second? %MyStruct{fiel▌}
should auto-complete. Perhaps you’re running into the case described at Auto completion for struct fields Elixir ls ?