Need help matching bind off to cast on

I’m redoing the sleeves to this cardigan (image and attached) and trying to match the bind off to the rest of the finished edges of the piece. In the image is the cast on edge that is 4x1 and I think it’s tubular but I am not too sure. I definitely don’t know how to go about doing tubular bind off for 4x1 ribbing, all the tutorials are for 1x1 and 2x2. I’m tempted to just go ahead and do it even though it’ll look a mess.

Appreciate all the help I can get!

Welcome to the forum!
Tubular or sewn bind offs are really pretty, organic finishes. I haven’t seem them for anything greater than 2x2 rib as you mentioned. I wonder if you could work the last row before the bind off in 1x1 rib and then use a tubular bind off. Other than that, maybe a stitch over stitch bind off in pattern may be an alternative.
What is the name of your pattern?

Thanks for the welcome! Unfortunately, cardigan is from a store so there’s no pattern. I didn’t like the flair of the sleeves so I frogged it from the cast on edge and knitted from there. I think your idea of knitting the last row in 1x1 before tubular sounds like it’ll work! Thanks so much!

See if you like the way it looks and let us know how you decide to finish the sweater. We’d love to see a photo when you do.
(I sometimes convert the pattern’s rib to 1x1 just so I can work a sewn bind off. )