I know exactly what you are talking about, as I used the be a Windows user. My experience with Windows is...
Windows 3.1 for workgroups
Windows 95
Windows 98 & SE
Windows NT
Windows ME
Windows 2000
Windows XP SP 1-2-3
Windows Vista
Windows 7.
And that's where my experience ended. Once support was gone on Win7, I jumped ship to ZorinOS. When your used to Windows, you have a lot of expectations.
Linux in general has been a 30-year work experience. The first 20-years, it pretty much was only a hackers OS or government use OS. Linux for the average desktop user, really only became a thing 12-years ago.
Today, it's much better then it was, but it has much farther to go if it wants to fully compete against Windows as far as features. But it's important to note, that it is getting better every year.
If you install Synaptic Package Manager, I think you'll find it's an awesome package manager. It of course will take time getting used to for a beginner. But it's better then Software.
You mentioned my favorite video editor Kdenlive, I love it, it can work with 4K videos. If you need a great photo editor, I recommend GIMP.
One of the things you will notice about Linux, most all software is free. Microsoft is in it to make a buck, all software is usually paid, and it's expensive.
The cost of Adobe Premiere alone should have you screaming, and you practically need a collage degree to learn how to use the darn thing!
Open source is the way to go. It keeps people honest, and is fair, everybody benefits. With closed paid software, the only people who are benefiting is greedy Microsoft and big company devs.
I know the switch is not easy. I gave up a lot when I first jumped ship. But things are better now, more support. The gaming department was still bad on Linux 6-years ago, much better now.
