That might be an overstatement, but his speciality was not the Force, no.
There's also a limiot to how much you can mess around in a Force sensitive's life before you get noticed, even with Obfuscation. If we assume that Sidious is the best then he is able to dangle himself under the nose of the Jedi continually whilst plotting their annihiliation and a mssive Galactic war without the Jedi ever being able to a. sense in general what was going to happen other than a sense of forboding and b. being unable to sense specific things like Kamino. All evry impressive.
Kuylen managed to fake his death and turn to the Dark Side without attracting Palp's attention. But (as the game plot went) people were starting to dream aout the consequences of his activities at Avalar, so when he started to try and effect galactic change his cover started to be blown. That said, he only had Sidious gunning for him after the Jedi made ttheir report. As often happens, the prosaic trumpos the mystical; Force or no Force, what Kuylen was doing had been found out. Sidious was then able to track Kuylen to Malastare (directing the Jedi there) though means unknown, the same way Maul was able to track QGGJ and co to Naboo via means never explicitly stated, so after that point he was an open target.
So, where does that leave Sienar? Well Sienar really is extremely powerful indeed, I don't want anyone in any doubt of that. He's also remafrkably perceptive- his future sense is something he was designed to be exceptionally acute at, allowing him to create these lduicrously convolugted manipulations that depend on so many things coming together (Xanatos Roulette, I believe it is called, though with the Force we have an excuse), and you will note that he has not actually tried to get any control in the Senate at all- bewcause he knows, or at least suspects, that would draw the attention fo someone else doing the same thing.