Haven’t followed any specific grounding principles for the RPi5 versions to date. They seem to have performed fine, though I have not noticed/heard about the TP73 tab. The risk with connecting the tab to a metal enclosure and the enclosure to the equipment is creating a ground loop, so I would be a little hesitant there.
The CM5 versions we have had tested in accredited labs to automotive standards for surges, induced noise/surges in all cables, ESD and radio immunity and it passed all. Surge testing was pretty harsh as well - dropping to -75V then going back to 12V repeated 5000 times. Tested up to +125V as well. Radio immunity testing showed that the enclosure + PCB was effective at handling radio noise across a large part of the MHz and GHz frequencies. So I am quite confident in the performance of the new design. Would 100% recommend using S/FTP high quality ethernet cables though. The shielding makes a huge difference.
Here’s the post on the CE testing, we’ll release all the test reports as well so everyone can check them out
CE Testing Starts on OWL3.0