Not sure I'm feeling the Olympus 75mm f/1.8...

I think you have made a very convincing case for why the lens is not for you.  Your needs are quite different.  I have the lens and am very pleased with it but then I like to take my images from further away in a more candid manner.  Likewise I have had a few macro lenses but they don't really light my fire.  The close focus distance on the 75/1.8 I think reasonable considering its intended purpose.

As an example of an awkward bird indeed I note that the (FFeq) 200mm f4.5 legacy lens made by Schneider Kreuznach for the Kodak retina in DKL mount had a close focus of 8 metres and is the only lens I know that has focus markings at 20, 25, 40 & 80 (!) metres before infinity.  Add that the manual focus ring is very close to the camera on this big heavy lens and it leaves no doubt that the built in tripod mount supplied must be used.  Takes great images only if you are masochist enough to persevere ...

1/150 seems an over-fast shutter speed limitation for the lens and maybe you should allow yourself slower shutter speeds with this lens.  I was able to get handheld shots at as low as 1/20 and sometimes lower without IS but on wider lenses.  But I now believe this to be rather optimistic.  But I do think that the old film based rule of thumb on shutter speeds versus focal length  limitations went out with the moving feast of adjustable and ever more capable ISO - not forgetting the benfits of IS where this is available.

Just tried the 75/1.8 on a GX7 (has IBIS) indoors, subdued light, shutter priority 1/25 f1.8 320  ISO.  Rough brick wall - sharp as a tack.

Give it a try - I would hate to see buyer's remorse deprive you of a great lens.  But of course if it does not suit your style of shooting then that is a quite different matter .....