Luminous prime for MFT (25mmf1.4 or 75mmf1.8) , or 12-40mmf2.8

Yes, I noticed those tilting adapters, probably the cheapest way to get that effect.

The problem with adapting old lenses is the lack of Image Stabilisation a feature we now take for granted. The loss of 2or 3 Stops flexibility makes a massive difference to very long shots..

Sorry, you have Panasonic bodies, I have an E-M5II and a fabulous IBIS ...

Aye  LOL  If, the GX80 feels good in the hand (the GX7 didn't, hence G6/G7), I might well trade/sell the G6 to get the GX80 but, by next week, the 100-300mm will have arrived and that might be enough.

There is another option that, apparently, works well with tehG7 and that is a canon 100-400 f4-5.6 L IS USM and a Metabones Smart adapter, which, surprisingly, would be much less cost than  the Panasonic 100-400mm but a tad heavier. Still, I could then strut with an enormous 'canon' over my shoulder like the pro Birders at RSPB reserves

Another point supporting the OP opinion : I own both the Panaleica 25mm 1.4 and the Olympus 75mm 1.8, and, on the other hand, a Fuji 35mm 1.4 APSC (so the same 50mm equivalent) ; however nice and useful, the Panaleica 25mm is not up the Fuji APSC sharpness and bokeh, and it is more or less the same bulk (and is more expensive), so I never use it when I have both bodies and lenses at hand and when I don't need IBIS. The 75mm is a much better buy, smaller and cheaper than the roughly Fuji equivalent 90mm 2, and it really makes the micro Four Third format shine.