I just wanted to say I've done extractions both ways on teeth that broke after root canals-before an abscess and after. It's more difficult after. Also, root canalled teeth are super brittle-so the crack will likely get worse.

Can you afford the implant later? I had an implant placed near the front a full year after the extraction wearing a flipper (the plastic fake tooth that pops in and out) the whole time. The implant is doing great now. I've also waited almost 5 years for my second molar to be replaced (so the teeth didnt shift since it was in the back), and I lost almost no bone.

In my experience when you already have a root canal, an abscess comes really fast, so you're better off addressing it as soon as you can.