Thanks for the notes, I'm glad to hear you're enjoying the aircraft! There is a lot of love for the TBM in the community, so I am always happy to apply fixes and port new features to it over the years.
I know I fixed the trim master switch issue a while back (awaiting the next update), but I'm surprised nobody else reported the window rain effects yet! I've just fixed that for the next update too. I also fixed the composite mode electrical issue a while back, which was a little less trivial to unravel.
The DME issue was actually just a display problem, rather than a radio problem, but it reminded me of a limitation with the aircraft, just in case you go looking after the next update. I boxed myself into a corner, because there is a limit on the number of NAV radios we can "spawn" in MSFS, and I need at least one to drive the DME holding. With the KNS RNAV, that leaves only one DME holding receiver to share between the pilot and copilot's DME unit. This means that whichever one is put into hold mode last will override the holding frequency of the previous one. With what an infrequently used feature this is, I figured it would go unnoticed in normal operations.
Lastly, I'm not surprised about the FD in MSFS 2024... Last time I checked, there were some undocumented changes made to the flight director that I had yet to fully investigate. I had hoped they would be reverted, but apparently not. I'll take a look later today, and see what I can learn about the new behavior.
Thanks again, and let me know if there is anything else I can do for you!