Now I’m worried if I’ve got my Bowden tube seated in the hotend correctly…
Just pull/push the tube with your hands. If there is no play you are good, but if there is:
Inspect the bowden tube ends and cut them if they are worn out
Push the bowden tube in the fitting.
While pushing it in, press the collet down
Then pull it out with a nail and then zip tie it
I found original clips too thin, zip ties are much better IMO. It helped me remove stringing completely while using half of the retraction distance (using 0.6 nozzle)