Microsoft completely failed with those account hell. It supported one email with multiple account types like personal, work, schole. I don't know what the idea behind this. Who designed this system? If my organization creates an email for me it is for work. If i created an email it is for personal usage. Reason for this complication is that acount type chaos.
And now even Micrososft it self can not deal with those complications and disabled new teams to use personal accounts. I dont know any other software which is disabled usage of their customers' accounts. I think you are the one MS. Congratulations!
So i can not use new teams desktop and has to use web version. In the past because of your chaos in account types i have had created (by mistake) a personal account and bound some organizations with that personal account as guest. Now it is not possible to tell them allow my work account. And i forced to use Web version. If i could, i give up using the Teams. But organizations that i play part uses it.
My suggestion is to not use Teams as a collaboration tool, If you are starting a new project.