From working many no seam sweaters in the round I don’t think the weight would be an issue with circulars. When it gets large most of the weight is laying in your lap. I could add as many stitches to the sweater as I wanted and all of the added weight is down the cables laying in my lap.
There will be a lot of shifting. At least with a sweater that just amounts to picking it up so it recenters.
I do have a large blanket started but it’s a light yarn. I don’t see any problems starting.
Large crochet blankets, which I have done in heavy yarn, are the same way. The weight is where you’re working, the rest is in your lap.
Straight needles would be a different story, then you would be holding all the stitches on the needles.