I attended dispensationalist churches for a while after the cult, but I never really absorbed their theology.
My exposure was more through friends. Lately, I was searching for a church and the pastor of the church is dispensational. Most of the reason why I started studying it is because of that.
I was shocked to find out that as a rule, they don't believe that the New Covenant is for the Church.
I have been trying to study the topic for over a year, though. I kept putting it off because I knew it would be a long, hard study.
I don't consider dispensationalism to be cultic, or don't have strong issues with dispensationalist brothers, though. It really just rubs me the wrong way that they intentionally misrepresent Reformed people as being anti-Semitic and use words like "spiritualize" and "allegorize" to combat those who hold the covenant theology position.
I should say, though, that the cult taught some things similar to dispensationalism. It is likely because they came out of the Millerite movement, and some within dispensationalism were affected by these teachings in a way.
If you're interested in the historical aspects of dispensationalism, here's a few resources, both by speakers who were dispensationalists before.
This guy named Bruce Gore has a good church history class where he mentions these things.
Bruce is from a PCUSA congregation which is very liberal as a whole, but his church is not part of the liberal ones.
Also, here's three more by Brian Borgman. He is a conservative Reformed Baptist:
https://www.sermonaudio.com/sermoninfo.asp?SID=126101523139
https://www.sermonaudio.com/sermoninfo.asp?SID=126101519187
https://www.sermonaudio.com/sermoninfo.asp?SID=126101510492
I should say, I believed at least some elements of dispensationalism, as it was a shock to me to realize that their interpretation of Revelation 20 is really the only evidence to support their claim, and if it is not true, then the entire system falls apart. I started realizing that if you read Scripture using their hermeneutic, there is a battle prior to the Millennium, and then at the end of the Millennium. And, I was exposed to the idea by a friend who had recently become postmillennial that Revelation 20 isn't part of a sequence beginning at Rev 6, but that Revelation is a series of visions with overlapping content. That's really what broke the spell.
Then, realizing that dispensationalists were slandering covenant theologians through claiming that they were "spiritualizing" and "allegorizing" text, as well as claiming they were anti-Semitic, really discredited them in my eyes. I never heard any covenant theologian saying any bad thing about Jews, as, obviously, they know Jesus is a Jew. Martin Luther may have become angry with Jews, and the Roman Catholic Church may have said/did unfortunate things, and fringe groups might be anti-Semitic, but those acts of individuals don't reflect any more on covenant theology than they do on dispensationalism.