I'm sorry, but that is a complete and utter mess.. having to deal with several different systems, several different providers and several different manufacturers. That's one of the reasons I moved away from Linux - several different providers and when something goes wrong they all blame someone else. Maybe I'm just not intelligent enough to manage all of that.. sticking with Apple just seems simple.. and it all works.
What you call a mess, others call choice.
You asked how it could be done and I just presented some options - you don't
have to use all those different providers; just pick one each from the list. OneDrive and Your Phone, for example, are baked into Windows 10; Chromecast is deeply embedded in Android so it makes sense to go with those for ease of integration. Send Anywhere has apps for Windows, ChromeOS, Android, iOS, macOS...or just via the Web. This kind of cross-platform support doesn't exist in Appleland.
AirDrop is great, but to a Windows PC or Android device? Can't do it. AirPlay your screen to, say, a Smart TV (without an Apple TV box)? Nope.
Sticking with Apple is indeed simple and works well but it simply doesn't play nice with others. The costs are getting ludicrous and it increasingly feels like a trap - every part of the ecosystem is designed for maximum lock-in. Probably the best examples of this are the Watch and HomePod - both nice devices but useless without an iPhone.
If Sonos, Samsung, WearOS and Fitbit can make their devices cross-platform, why can't Apple? They choose not to - and that's starting to grate when even existing customers are expected to pay more and more for each new iteration of product.
Conversely, anyone happy with the cost and ease of the Apple ecosystem is
absolutely right to keep using it. As Federico Viticci says, it
erases complexity - and that has definite value to those willing to pay the entrance fee.