I don't know what sources you follow, but an op-ed by a right wing American-Israeli activist in the Jerusalem Post (itself not a particularly high quality newspaper) who is pushing a deep state conspiracy is not a reliable source of news.
I extensively read and follow mainstream Israeli news sources in Hebrew, and I have heard no credible doubt in the veracity of the video or whether the individual was in Sde Teiman (in any case, the soldiers were arrested before the video was even released). I have not seen the video and do not intend to do so, but the very serious injuries he suffered which are documented in medical records are consistent with the allegations. More specific details of these reported in the Israeli media, which I am not going to repeat here.
And no: no Israelis (well at least no sane ones) are saying that Oct 7 was "let happen". This is also even more absurd than the deep state allegations. It is inconsistent with everything we know about Oct 7, including Sinwar's planning (even if we supposed somehow it was known about - the plan focused on kidnapping civilians from kibbutzim).
Please, if you want to know what Israelis are thinking, replace your "sources" with some actual news that's connected to what real Israelis are experiencing and thinking, not some tiny fringe of right-wing conspiracy theorists in the West Bank, who are trying to somehow discredit the video and the entire justice system in a transparent attempt to deflect attention from the actual incident itself.
English sources do tend to be much less well informed than Hebrew ones and/or to have a very strong agenda. For those looking for something that reasonably accurately gives insight into the mainstream Israeli news, I have often recommended on here the podcast Unholy, which is co-presented by Yonit Levy, an anchor of Israel's most watched, mainstream, news broadcast (channel 12) and has knowledgeable guests. Friday's episode talked, among other things, about the Sde Teiman affair.