So I did some research and found a solution dated 2018, that I implemented. I have a different error now.
Request: GET /topics/new
** (exit) an exception was raised:
** (UndefinedFunctionError) function DiscussWeb.TopicView.render/2 is undefined (module DiscussWeb.TopicView is not available)
DiscussWeb.TopicView.render("new.html", %{changeset: #Ecto.Changeset<action: nil, changes: %{}, errors: [title: {"can't be blank", [validation: :required]}], data: #DiscussWeb.Topic<>, valid?: false>, conn: %Plug.Conn{adapter: {Plug.Cowboy.Conn, :...}, assigns: %{changeset: #Ecto.Changeset<action: nil, changes: %{}, errors: [title: {"can't be blank", [validation: :required]}], data: #DiscussWeb.Topic<>, valid?: false>, layout: {DiscussWeb.LayoutView, "app.html"}}, body_params: %{}, cookies: %{"__gads" => "ID=bb87c45b4ea925ba-22f91ec9b6d3008e:T=1653065583:RT=1653065583:S=ALNI_MZ-UckDPUlsKS2DJRQ5R-4UyhAk2g", "__gpi" => "UID=0000072ea6d60b8d:T=1653065583:RT=1653323020:S=ALNI_MbHCVMKuGf2sQn8u_vGBrMGWkIyZw", "_discuss_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYZUgzUlQydkZCa05wTlp0clZBeTdQRy01.wtEEbADSSVa1c1JOOy3KovyTMxXSMT_upyl4H7GYkzk"}, halted: false, host: "localhost", method: "GET", owner: #PID<0.588.0>, params: %{}, path_info: ["topics", "new"], path_params: %{}, port: 4000, private: %{DiscussWeb.Router => {[], %{Plug.Swoosh.MailboxPreview => ["mailbox"]}}, :before_send => [#Function<0.20795500/1 in Plug.CSRFProtection.call/2>, #Function<2.36663997/1 in Phoenix.Controller.fetch_flash/2>, #Function<0.84243074/1 in Plug.Session.before_send/2>, #Function<0.11807388/1 in Plug.Telemetry.call/2>, #Function<1.100171616/1 in Phoenix.LiveReloader.before_send_inject_reloader/3>], :phoenix_action => :new, :phoenix_controller => DiscussWeb.TopicController, :phoenix_endpoint => DiscussWeb.Endpoint, :phoenix_flash => %{}, :phoenix_format => "html", :phoenix_layout => {DiscussWeb.LayoutView, :app}, :phoenix_request_logger => {"request_logger", "request_logger"}, :phoenix_root_layout => {DiscussWeb.LayoutView, :root}, :phoenix_router => DiscussWeb.Router, :phoenix_template => "new.html", :phoenix_view => DiscussWeb.TopicView, :plug_session => %{"_csrf_token" => "eH3RT2vFBkNpNZtrVAy7PG-5"}, :plug_session_fetch => :done}, query_params: %{}, query_string: "", remote_ip: {127, 0, 0, 1}, req_cookies: %{"__gads" => "ID=bb87c45b4ea925ba-22f91ec9b6d3008e:T=1653065583:RT=1653065583:S=ALNI_MZ-UckDPUlsKS2DJRQ5R-4UyhAk2g", "__gpi" => "UID=0000072ea6d60b8d:T=1653065583:RT=1653323020:S=ALNI_MbHCVMKuGf2sQn8u_vGBrMGWkIyZw", "_discuss_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYZUgzUlQydkZCa05wTlp0clZBeTdQRy01.wtEEbADSSVa1c1JOOy3KovyTMxXSMT_upyl4H7GYkzk"}, req_headers: [{"accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9"}, {"accept-encoding", "gzip, deflate, br"}, {"accept-language", "en-ZA,en-GB;q=0.9,en-US;q=0.8,en;q=0.7"}, {"connection", "keep-alive"}, {"cookie", "__gads=ID=bb87c45b4ea925ba-22f91ec9b6d3008e:T=1653065583:RT=1653065583:S=ALNI_MZ-UckDPUlsKS2DJRQ5R-4UyhAk2g; __gpi=UID=0000072ea6d60b8d:T=1653065583:RT=1653323020:S=ALNI_MbHCVMKuGf2sQn8u_vGBrMGWkIyZw; _discuss_key=SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYZUgzUlQydkZCa05wTlp0clZBeTdQRy01.wtEEbADSSVa1c1JOOy3KovyTMxXSMT_upyl4H7GYkzk"}, {"host", "localhost:4000"}, {"sec-ch-ua", "\"Google Chrome\";v=\"105\", \"Not)A;Brand\";v=\"8\", \"Chromium\";v=\"105\""}, {"sec-ch-ua-mobile", "?0"}, {"sec-ch-ua-platform", "\"Windows\""}, {"sec-fetch-dest", "document"}, {"sec-fetch-mode", "navigate"}, {"sec-fetch-site", "none"}, {"sec-fetch-user", "?1"}, {"upgrade-insecure-requests", "1"}, {"user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36"}], request_path: "/topics/new", resp_body: nil, resp_cookies: %{}, resp_headers: [{"cache-control", "max-age=0, private, must-revalidate"}, {"x-request-id", "Fxi8u-YuyJjo--QAAAFD"}, {"x-frame-options", "SAMEORIGIN"}, {"x-xss-protection", "1; mode=block"},
{"x-content-type-options", "nosniff"}, {"x-download-options", "noopen"}, {"x-permitted-cross-domain-policies", "none"}, {"cross-origin-window-policy", "deny"}], scheme: :http, script_name: [], secret_key_base: :..., state: :unset, status: nil}})
(phoenix_view 1.1.2) lib/phoenix/view.ex:298: Phoenix.View.render_within/3 (phoenix 1.6.12) lib/phoenix/controller.ex:784: Phoenix.Controller.render_with_layouts/5
(phoenix 1.6.12) lib/phoenix/controller.ex:772: Phoenix.Controller.render_and_send/4
(discuss 0.1.0) lib/discuss_web/controllers/topic_controller.ex:1: DiscussWeb.TopicController.action/2
(discuss 0.1.0) lib/discuss_web/controllers/topic_controller.ex:1: DiscussWeb.TopicController.phoenix_controller_pipeline/2
(phoenix 1.6.12) lib/phoenix/router.ex:354: Phoenix.Router.__call__/2
(discuss 0.1.0) lib/discuss_web/endpoint.ex:1: DiscussWeb.Endpoint.plug_builder_call/2
(discuss 0.1.0) lib/plug/debugger.ex:136: DiscussWeb.Endpoint."call (overridable 3)"/2
(discuss 0.1.0) lib/discuss_web/endpoint.ex:1: DiscussWeb.Endpoint.call/2
(phoenix 1.6.12) lib/phoenix/endpoint/cowboy2_handler.ex:54: Phoenix.Endpoint.Cowboy2Handler.init/4
(cowboy 2.9.0) g:/docs/github/elixir/discuss/deps/cowboy/src/cowboy_handler.erl:37: :cowboy_handler.execute/2
(cowboy 2.9.0) g:/docs/github/elixir/discuss/deps/cowboy/src/cowboy_stream_h.erl:306: :cowboy_stream_h.execute/3
(cowboy 2.9.0) g:/docs/github/elixir/discuss/deps/cowboy/src/cowboy_stream_h.erl:295: :cowboy_stream_h.request_process/3
(stdlib 4.0.1) proc_lib.erl:240: :proc_lib.init_p_do_apply/3
