A 'special' locomotive CSX #1, part of the administrative CSX 'Office train' captured in Tampa this week with my EF-modded EF-S 55-250 IS STM lens and Kenko 1.5x SHQ 5-element teleconverter, along with other shots from this week.
I removed the chip from the TC so it's now pass-through electronics and doesn't report to the EXIF data - the image captions contain the correct focal lengths and apertures. The TC combo didn't work properly with the chip installed, but without the chip, lens AF and IS work as expected on the M6ii.

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 375mm, f8, 1/1600s, ISO 160. Distorion is due to 'heat shimmering' in the distance as the train was nearly 1/2 mile away

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 200mm, f7.5, 1/640s, ISO 160
Yellow-crowned night heron kicking back a small crab for dinner, 1.5x teleconverter at ISO 20,000 with DxO PL5. (Used my technique of under-exposing at ISO 3200 and pushing in post to get 2+ EV of extra dynamic range with the low-light perf of ISO 20k).
I get a kick out of the recent YouTube Canon R7 reviews gushing at how good the R7's low-light ISO performance is with DxO or Topaz de-noise, as if this is a 'new thing' ---- The M6ii's sensor has been delivering this great high ISO performance since DxO and Topaz stepped up their de-noise algorithms a couple years ago!

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 310mm, f8, 1/100s, in-camera ISO 3200, pushed to ISO 20,000 in DxO PL5

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 375mm, f8, 1/160s, in-camera ISO 3200, pushed to ISO 20,000 in DxO PL5
Tiny birds from about 30 feet away, with Kenko 1.5x TC

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 375mm, f8, 1/1600s, ISO 640

Canon M6ii, EF-S 55-250 IS STM, Kenko 1.5x SHQ teleconverter, 375mm, f8, 1/1600s, ISO 640