I do believe there is a serious rift between William and Harry. But I don't think it's permanent or beyond repair. Their intrinsic bond is strong. The core is deep. They will find their way back to each other.
Bertie and David never found their way back to each other, but I believe with all my heart that it was FELT between them. Bertie knew. David knew. They knew each other. So it is with William and Harry. They know each other. Deep down. And it's a question of when they are ready to admit it.
What was "felt" between them? THey probably always had some affection for each other, but David was bitter against his family, including his mother, for their rejecting him as he saw it. I don't think he ever really forgave them. He and Wallis were pretty much negative against the BRF because they felt that they were unfairly treated. And Bertie also felt badly let down by his brother and never quite got over it.
They appeared everywhere together when they were younger, then as in all families change happens, one brother goes to university in Scotland , the other is still at school then joins the army.
Other than holidays, maybe not even then,they do not see as much of each other. That is not any different to lots of families.
It has also been documented that William spent a great deal of time with the Middleton family.
Even when they all stayed within KP, Harry was a single man, leading a different lifestyle to his married brother with a wife and family.
Separation does not reduce the love or closeness of a family it just limits the physical contact.
I just wish them all well.
The thing is, in olden days, Royal families were kind of forced into being close in a way. Only other royals were tehir equals, so they had to be each other's best friends. Of course they had their ups and downs, but the situation that no one else knew what it was to be Royal probably caused closer relationships among royals. However in today's world, its different. Royals do ordinary jobs, they mix with a wider variety of people, class wise and so relationships form. They meet with people that they would never have gotten to know, 50 or 60 years ago.
Years ago, people marrying into the RF were expected to be with them during festivals like Christmas, and not visit their own families. Now that's changed. William spent a lot of time with the Middletons and probably found them pleasantly informal... and even now, he probalby spends as much time with his in laws as he does with the RF.
Harry was outside that relationship, and had his own friends. He loved William but spent less time with him. When Kate married WIlliam, I think they spent a bit more time together for a while but Harry and Will are freer to find their own circles of friends than was the case 40 years ago.
Perhaps Harry felt a bit excluded if he was hanging out with his brother and his brother's wife and kids... He wanted to find a woman he could settle down with.. who would be his best friend.. and he found her.. but she didn't settle in the UK and now they have moved away. Possibly Will is upset by this or a bit resentful at being left with the royal duties that Harry has walked out on. Perhaps Meghan after the first few meetings, didn't take to the RF as a whole or they didn't take to her and its caused tension.