Delphi isn't outdated by any means. It has a vibrant update rate and is fully cross-platform and everything else you would need in modern times.
As for tutorials, they aren't necessarily old, they're just scarce seeing as how it's not a big community of users (mostly enterprise and big business) so that's why you're not finding many.
90% of old tutorials still work on modern versions, very few requiring small adaptations to code.
A good place to start is the full
Help Docs the IDE offers / Embarcadero's website.
Then you can try the Embarcadero webinars, they have them very frequently and are updated constantly in the form of videos, uploading to the youtube channel. Hours and hours of examples and such.
Other than that you can try board4all forum, it's a VERY big and vibrant Delphi community over there.
Lastly, read this thread:
https://hackforums.net/showthread.php?tid=5724188
There is a list of books and online resources there that are current and accurate.
Finally, books are the main way to go!
You can find a list of books still relevant (regardless of their age) here:
https://hackforums.net/showthread.php?tid=5733625
From that book list, I'd recommend starting and reading the following entirely, they're code is accurate for current Delphi versions:
Object Pascal Handbook - updated for Delphi 10.1 Berlin - Marco Cantu [2016]
More Coding in Delphi - Nick Hodges [2015]
Delphi Cookbook - 50 recipes to master the power of Delphi for cross-platform and mobile development on Windows, Mac OS X, Android, and iOS - Daniele Teti [2014]
Coding In Delphi - Nick Hodges [2013]
Delphi 2009 Handbook - Marco Cantu [2009]
Delphi 2010 Handbook - A Guide to the New Features of Delphi 2010 - Marco Cantu [2010]
Recipes to Master Delphi for IoT Integrations, Cross-Platform, Mobile and Server-side Development, 3rd Edition.-Packt Publishing Ltd (2018)
Paweł Głowacki - Expert Delphi - Robust and fast cross-platform
application development
That's more than you need for the current version of Delphi.
Other than that, you can always try StackOverflow if you have questions.
Good luck :)