I am unable to install apps on my Apple Watch

I see that you are currently using iOS 15 which is an older iOS version and that you are using an iPhone 7. When I was using my older iPhone to connect to an Apple Watch and transfer data it was remarkably slow like in your situation. Maybe if you don't download all of the available apps all at once and opt out of the transfer and then download the apps you want one at a time you may be able to eventually get all of the apps you want and use your Apple Watch again.

It may be beneficial and convenient to upgrade to a newer phone that can run the latest iOS software which I think could help in this situation.

I hope this information helps, however I am providing this information from the perspective of another consumer and not an expert so take my advice with a grain of salt.

Good luck!

BatCatDog wrote:

When I press i stall on my available watch apps, the little circle just goes round n round, never transfering

Because the automatic information about what devices and systems you're running is notoriously inaccurate, can you confirm what model watch/version of watchOS and what model of iPhone/version of iOS?