Need tech savvy post instalation

nextcloud version _: 15.0.2
Operating system and version : ubuntu 18.04
Apache or nginx version : apache 2.4
PHP version _(: php 7.2

hallo, first time posting here. i now i am curretlly making nc with latest version and want to use it in lan environment without connect to internet, just for personal use.

after i install i notice several things and i hope you guys can help me what should i do about my case.

  1. notice that i can only access nextcloud with address either of that it will forward to apache congrat page.
  2. if i target my ip address of my nc server, (ip adress/nextcloud) error show up about trusted domain
  3. is installing ssh or the needs to switch to https is neccesary even in local LAN environment network?
  4. i do think i this is pretty much mess up post instalation. should i reinstall without reformating my linux? i am not using VM to build this.

thank you for reading this.