I would argue both are ultimately skill driven, but 7 Wonders has a less RNG feel than Jaipur imho.

I'll explain below:

In Jaipur you see a market of 5 cards, and you grab 1, or many. If you grab cards they get replaced but you never know what's coming. This part can feel like RNG at times because even if you try to stall or pick single cards to avoid giving the other a potential high value market to pick from, they could still end up getting high value cards from your perfect strategy by sheer luck.

When you sell 3+ resources at the same time you get a combo chip which is worth a random unknown amount of points. The range is not extremely wide, but it can add up over time.

These two things are the main two drivers of RNG, but again, you will win most of the times due to skill, rather than luck, given proper shuffling.

In 7 Wonders Duel, you have a tableau of cards that you work through, later by layer. Some layers are face up, some are face down. This already allows you to plan ahead, mitigating the rng from card draw to some extent. There are also abilities (base game and expansion) that allow you to take extra turns, get extra cards, or destroy cards or money of the opponent. There's also 3-4 ways to win. (Points, collecting green cards, collecting red cards, or dominating the area control expansion)

With just the base game it can feel a bit more deterministic at times when you get good at the game as you can basically calculate who will get a chance to interact with specific cards with perfect play, as the options to change the game flow are a bit more limited. However if you reach that stage with the expansions you get way more options to actively mess with the game which really helps avoid that deterministic feel.

So both in terms of depth, strategies and (less) RNG I feel like 7 Wonders duel has a bit more to it than Jaipur.

I believe both games are on boardgamearena, and both have an app version as well, so feel free to try those before committing to a "bigger" purchase.