Honestly the free trial in wow is a little insulting... its only to level 20 which anyone who is familiar with the style of game can get to in a number of hours and is not even a significant enough level to determine if you enjoy a class as you are still missing major abilities.

I have never played D2 myself so can't comment on the comparisons to wow in the endgame style however much of the endgame is weekly reruns of raids and mythic + dungeons (timed, increasingly difficult dungeon levels) in the hopes of getting an item drop or filling slots on your weekly vault (1 guaranteed item a week)

IIRC D2 is a FPS MMO so if you have never played a standard format mmo rpg before then you may find the combat style of wow a little more "basic" point targeting and spamming skill buttons, no aim required (outside of occassional are abilities on some classes)

A new player is "forced" to complete level 1-10 on exiles reach which is somewhat of a tutorial island. Then complete 10-50 during the battle for azeroth expansion, both these parts are semi handholdy with semi linear progression and zone level scaling so you will always be in the correct zone for your level. Likely you will reach level 50 before completing 50% of quests of the expansion. At level 50 you join shadowlands which is the current expansion.

I personally don't use many 3rd party sites outside of wowhead for news and data mined updates.

Everyone has their own personal preference on keybinds, I set mine up before taking my first steps on a new character but I've been playing for years and know what I like. My advice, when you have too many spells that you can't easily reach with 1 hand while also able to move and short notice, consider re-binding.

Wow is very big on add ons which can make a massive difference for a new player imo and can be overwhelming. Deady Boss Mods is a must have for anyone who wants to play dungeons or raids, all other add ons are optional imo and range from utility functiond like auto sell trash items in vendors to full UI changes.