Loaded should be fine if they're operating as they did when their name was CDKeys. 👌

gamesplanet.com should be legit, see my other comment in this thread. As a result they have pretty high prices compared to the shady sites though. My main use case is throwing some money at an independent games journalist I like through his affiliate link (and getting a 10-20% discount in the process)

on gg.deals you can compare multiple ones, then filter the store section for "official"

edit: loaded is a keyshop, not an official one