Hello, I went to replace the cartridge and you can guess what i found on the internal puller threads for the L arm.
Should I:

A. Bolt it back together w a new cartridge. I understand it's a UN55 Shimano. 68mm x 110mm (some list it as 110.5, which is accurate). The arm appears to have survived the removal, but I question if it will survive the next disassembly. Largest sprocket (42T) is worn, but really not needed, the 32t is fine for blacktop.

or

B. Is there a way to install a hollow two sprocket crankset?
For starters, I don't understand how spindles are measured-
Only one lists length: 1180mm- which is almost as long as the bike.
I'd assume there's different offsets, not to mention cartridge length, threads- and then tooth count and chain size.

I really don't believe it needs three sprockets- just using the 32 and 22 works.

And you could also predict where my price range lies ...

Just out of interest, cartridge is branded 'TH,' would this have been an aftermarket replacement or (possibly) original to Trek? I'd assume Shimano crankset would use a Shimano cartridge. Someone obv has had it out as it was rusty, but covered with fresh grease.

Thanks in advance, the bike is far better than my previous one.