Thank you. No issues to be expected if one would really milk an METV like that? No issues with actual border bounces / stays outside of Thailand only for a few hours or days?
Turn the annoying inconsistencies between offices and officers into your advantage. Try first: Go another day, hoping for another officer. If that does not work, go to another office in another district. This is the general fix for issues at the immigration office, imho.
Possible, that the Thai consulate in France handles it that way. Like with everything Thai (immigration or consulate) every office tends to have deviating rules.
So, if that is a requirement, you could only go the e-visa route there, if you have an exit stamp out of Thailand at the time of submitting an application, it seems.
No need to renew the license before it expires, just because you meanwhile have a different passport number. May not even be possible - extension of drivers license only possible 3 month before expiry, I believe.
It is and remains a big pain in the behind and a logical (is there such things here in Thailand) flaw to bother foreigners with that TM30. In an ideal world a foreigner would extend at an address and immigration would then do random checks if the landowner reported that foreigner. But: TIT.
Get a reputable insurance from your home country. That way, you know (or should know) how to enforce your rights. Never had any issues. HanseMerkur for Germans / Europeans.
In most Immigration offices you do need a TM.30 for extending, yes. And yes your accommodation has to file those within 24 hours. BUT: For you effectively it makes no difference when the TM.30 was actually filed. It is sufficient to just present one at the time of extension (no matter if it was filed within 24 hours or an hour before you show up for your extension).