TLDR: It would appear that new Clara BW devices have a new product name "spaBWTPV" and model number 395, and the code needs to account for that.

I installed Plato 0.9.44 via the one click install package on a new Clara BW purchased last week.
Upon clicking "Plato" from NickelMenu, the device freezes until I hold the power button to restart it.

I was having a similar issue with koreader and found this, and adding the new codename did allow koreader to start, so I thought there might be a similar issue with Plato. I looked through .adds/plato/plato.sh and found this section:

Next I checked .adds/plato.info.log, and found:

OK
Plato is running on a Kobo Touch A/B.
The framebuffer resolution is 1072 by 1448.
Can't update [0, 0, 1072, 1448]: can't send framebuffer update: EINTR: Interrupted system call.
Can't update [807, 0, 871, 67]: can't send framebuffer update: EINTR: Interrupted system call.
Can't update [0, 0, 1072, 1448]: can't send framebuffer update: EINTR: Interrupted system call.
Went to sleep on August 26, 2025 at 11:35:38.
Woke up on August 26, 2025 at 11:36:15.
OK
Plato is running on a Kobo Touch A/B.
The framebuffer resolution is 1072 by 1448.
Can't update [0, 0, 1072, 1448]: can't send framebuffer update: EINTR: Interrupted system call.
Can't update [807, 0, 871, 67]: can't send framebuffer update: EINTR: Interrupted system call.

I am definitely not running a Kobo Touch A/B, so I went digging a bit more and found this which suggests that the product name is not being matched:

Since the existing Clara BW product name is "spaBW", I would suggest that "spaBWTPV" should also be supported, as that was the fix for koreader. I haven't tried to build this myself, so this is where my investigation stops at least for now.