Hi @Olias ,
If have had plenty of clogs for a whole bunch of reasons. But they were almost always with the .4 rather than the .2.
Since you describe the clog occuring around 6h into a print, heat creep does sound like a reasonable diagnosis.
With PLA, I usually target a chamber temp of 35-39°C to eliminate warping while avoiding heat creep. However, with many retracts, ironing and low flow (.2 nozzle!), I usually try to stay below 35°C. I expect that similar chamber temp windows exist for other materials (I think you mainly print PC?) which may be quite narrow in low flow conditions.
Speaking of flow, with a given chamber temp, cold end cooling options are rather limited. To counter the heat creep, using a smooth timelapse may give the option to get rid of some of the cold end heat build up in the prime tower. It is wasteful but can be checked in the flow preview.
Another thing which can counter heat creep in the borderline region is related to the filament thermal conductivity. High conductivity filaments are much more prone to heat creep than low conductivity filament with low flow. So if the problem occured with black filament, where a common pigment is carbon black, you may already be able to improve by going for a different color.
Or something really weird which was discussed a while ago in the forum: Blowing air down the PTFE using a small fan and a y-splitter. As I do not have an H2D, I am not sure if that is implemented there. I have not tried it myself so I can not comment on its effectiveness or detrimental side effects.
Edit: Link to post: Extruder cooling strategies? - #5 by RocketSled
Besides all of this, there are of course other major causes for clogs. A lot of stuff following the PTFE paths (which you are well aware of), and of course: plain bad luck, i.e. filament ovality, dust, dirt, etc…
Another point of note is the unclogging procedure. A successful reverse extrusion passes possible contaminants back through the extruder where they may get dislodged and sit there like little monsters biding their time… Took me ages to understand that travelling clog the first time I had that. It is also the reason why I only do hex key cold pulls these days, despite the hassle.
Best wishes, 
& 
,
Yours,
Eno