Chain length help

I just want to make sure I'm not doing something dumb before I shorten my chain!

I bought a used touring bike (on here), Croix De Fer frame. The previous owner had it equipped with 42T/30T chain rings and a 12-28 cassette. This was a bit of a tight range for me, but he had a spare 11-32 (11-speed) cassette, so he put that on before he sold it to me.

Still, quite a tight range; the highest gear was quite low for me (42T/11), so I changed the big chainring to a 46T, and thus I needed a new chain.

I also discovered that it's not a 32 cog, but a 34 cog on the cassette, so the bike now has quite a wide range.

I've put the new chain on, but I'm having issues with the rear derailleur. In small chainring and 4th smallest cog (ie. 4th highest gear) the chain is rubbing on the jockey wheel cage.

Seems like the chain is too long, which is understandable since I have 46T chainring and 34 cassette; that's a lot of teeth. I've measured and remeasured using the 2 popular protocols; the formula (I have a 16.75-17ish inch chainstay) which gives 55 inches for the chain. Also wrapping the chain round the big cog and big chainring and subtracting 1 link also gave the exact same length.

Basically my gear range is too wide! I just wanted to check that it's sensible to remove another link. This would pull the jockey wheels away from the cassette, and offer much more clearance when on the small chain ring.

On the big chainring and big rear cog, the jockey wheel is pulled forward more than 45°, but I think it would be fine with 1 less link on the chain. And besides, I'd rather not have big chainring big cog than not have small chainring and highest FOUR cogs.

Just FYI, the B-Screw is all the way in, so there's no room to budge on that.

If the B-Screw is in the right position I'd chop it as long as possible but maintaining enough tension to avoid the chain being floppy or the derailleur interfering with itself.
But maybe what you need is a longer derailleur.

I don’t see how chain length is going to solve your problem. That will pull the lower jockey wheel further forward but the upper one will stay in the same place. B screw is the only thing which moves both away from the cassette.
My method for chain length - which I think is shimano’s suggested method, is chain around the big ring and big cog, not through the derailleur and add 2 links.

Photos will maybe help

But maybe what you need is a longer derailleur.

Yes, I think that might be the "proper" way to solve this. My cage is 55.5mm which I believe is a short cage, suitable for 11-28T cassettes.

Hopefully I can find a longer cage without having to replace the entire derailleur.

That will pull the lower jockey wheel further forward but the upper one will stay in the same place

Yes that's what I need. Currently in small chainring and smaller rear cogs, there is so little tension on the jockey wheel that both jockey wheels are roughly the same height, thus the chain comes out of the "lower" jockey wheel and is rubbing on the cage of the "upper" jockey wheel.

is chain around the big ring and big cog, not through the derailleur and add 2 links.

Yes, sorry that is what I meant. I went back another link and am also using a powerlink, so that's 2 extra links.

A longer cage would certainly take up more slack. You have something like 39t difference between extreme gears and a short cage is unlikely to be rated for that much so I suspect it’ll be too tight in the biggest and too loose in the smallest combos

Update: Had to get a new rear derailleur. A medium cage SRAM Rival one did the job. Thanks for your help!