paramount+ on TV App

Yes, but there are two versions of subscriptions. If you subscribed directly using Paramount's app on Apple TV (which would still be billed through your Apple account and show up under your subscriptions) then you would have to use the website to access on Mac. It is only if you subscribed through the Apple TV app that it will be available through there on Mac. This would be designated as an Apple TV Channel under your subscriptions.

If it's a subscription through as an Apple TV channel, then you should be able to watch it on Mac's TV app.

If it's a separate subscription (directly with Paramount+), then maybe on Mac you need to access it via browser (Paramount+ website).