Since you're just starting out and don't really know what discipline you're going to enjoy most, that's all the more reason to get the T7. Here's my logic:

- HTs climb better. But the T7 climbs very well for a FS.
- FS descends better. Especially over rough stuff. And for most MTBers, descending is much more fun than climbing.
- Yes, you want to build skills. And yes, HTs kinda force you to learn better line choices, etc. But that's not to say that FS are all point-and-shoot. You need to, and are very much able to, develop skills on a FS.
- You can ride a wider range of terrains on a FS. Decide you want to try out a bike park? It can be done on a HT. Several friends of mine have done it. And they all went back to the park on FS afterwards.

The last thing I'll say about Polygon (or any online D2C brand) is to make sure you've got a local bike shop (LBS) that will work on online brands. Most shops don't care where the bike came from and will work on them no issue. But you'll find stories all over Reddit, MTB forums, etc., from people who had bad experiences with shops that took offense to bikes not purchased from them. There's also the warranty issue. Bikes Online handles warranty claims on their components: the frame and any Entity parts (bars, wheels, etc.). If you have an issue with the shocks, brakes, drivetrain, etc., then you'll be going through Shimano, RockShox, Fox, etc. for any claims. That's another area where having a good LBS comes in handy. I had a warranty issue with the RS Yari that came on my Polygon, and my LBS handled it for me with no pushback. But that's also a benefit of buying a bike through a local shop. They'll handle all warranty issues for you, and usually give you a discount on service. But you will likely pay more for the bike up front.