I wouldn't think the converter would cause an engine bog. The heavier you are on the throttle requires more fuel and air to the engine. If it bogs when you request more power, the first thing for me is the fuel pump is weak or there is an air restriction to the throttle body.
Have you confirmed fuel pressure? Also, do you have a live data scan tool?
If you have a live data scan tool, let me know what the short-term fuel trims are at operating temperature. Also, if you haven't, you should check the fuel pressure. There could even be an issue with a filter restricting fuel.
Here is a link that explains in general how to test fuel pressure:
Let me know if this has already been done and the results.
Saturday, June 12th, 2021 AT 8:46 PM