I consider Notos (4 pounds bare) and the Benjamin Marauder Pistol/Carbine (2.7 pounds - add the stock weight) to be good for working on shooting skills and short range hunting carbines.
That's a very good price, I've never dealt with 'Airgun Revisions' though, but some here may have and can relate their experience. That ad claims 800 fps, doubt that without some modding. Mine got around 700 fps with 14 grain pellets.
One thing I do is go to Pyramid Air, look up the gun and read some of the good & the bad reviews, and look at the overall percentage that rate the gun 4 or more stars;
https://www.pyramydair.com/product/benjamin-marauder-pcp-air-pistol?m=2367 The Benjamin Marauder Pistol that I had, did not have any issues. With that said, I bought my first Benjamin Marauder 'Rifle' locally, it leaked badly, took it back to the dealer (hardware store), they exchanged it, that one also had an issue. They had no more to exchange so I called Benjamin/Crosman customer service, they paid for the return postage and replaced the gun after making sure the replacement had no issues (leak tested & shot it for accuracy). I was very impressed with their customer service. Note that this was 10 to 12 (?) years ago, so I do not know if their customer service is still top notch.
Regarding the Sig guns, in addition to the experience of those here, I would do the same - look at the reviews;
https://www.pyramydair.com/product/sig-sauer-asp-mcx-virtus-pcp-air-rifle?m=5130 Note that this gun weighs 7 1/2 pounds bare. Sig has several other similar guns that are CO2 (this version is a PCP).
Jerry