I have several older spools of Sainsmart TPU. The spools are wider and the ID hole is only 32mm. So a while back I made these Ender 3 spool holder modifications for use on these spools. In addition I had made a second version with a pocket to slide in a section of PTFE bowden tube to act as the sliding bearing surface for the spool to ride on.

Prints without supports and locks positively in place with detents using the original spool holder nut on the Ender3 and Ender3 V2 machines.

I have included the file in my naitive Solidworks format (2018), and also exported as STEP AP214. Please feel free to modify and remix to fit your needs.