There are also some places like https://glitchwave.com/ and https://backloggery.com/. I haven’t tried them. but at least theoretically they could offer advantages like game library import and easy game adding, provided they offer something like CSV export.
Edit:
https://www.grouvee.com/
Edit 2: Backloggery does not currently offer export. It says it’s planned.
Edit 3: Glitchwave is not taking new members. That leaves Grouvee and less likely HowLongToBeat as potential spreadsheet alternatives.
Edit 4: Grouvee supports export! But is it any good compared to a spreadsheet… let’s give it a quick try.
Edit 5: hm, I don’t know… on the plus side you can search for a game and click add, on the downside the interface is… I don’t know, touch idiocy or something?
The export has JSON in it. Looks like this:
id,name,shelves,platforms,rating,review,dates,statuses,genres,franchises,developers,publishers,release_date,url,giantbomb_id
51040,Shadow Tactics: Blades of the Shogun,"{""Played"": {""url"": ""https://www.grouvee.com/user/Frenzie/shelves/501425-played/"", ""date_added"": ""2019-01-19T11:19:51Z""}}",{},5,,[],[],"{""Strategy"": {""url"": ""https://www.grouvee.com/games/?genre=strategy""}, ""Real-Time Strategy"": {""url"": ""https://www.grouvee.com/games/?genre=real-time-strategy""}}",{},"{""Mimimi Productions"": {""url"": ""https://www.grouvee.com/games/?developer=mimimi-productions""}}","{""Daedalic Entertainment"": {""url"": ""https://www.grouvee.com/games/?publisher=daedalic-entertainment""}}",2016-12-06,https://www.grouvee.com/games/51040-shadow-tactics-blades-of-the-shogun/,53650