Most receivers around are adequate for 136 khz reception of radio
amateur signals.
Basically all that is required is a narrow IF filter especially at the
the last IF normally 455 khz to avoid adjacent channel qrm. At the rear
end a good audio filter.
I have a selection of 4 modern receivers some with dsp like the ft 1000.
Some are marginally better than others but all are totally acceptable.
My qth is non hostile, quiet environment, away from loran, mf or lf
broadcast station etc.
If you are unfortunate and live in a HOSTILE area, plaqued by every
conceivable noise then your receiver requirements are critical and
perhaps there is no receiver manufactured that  will cure your problem.
In extreme cases moving qth is the only way forward if one insists on
working LF.
Try an old tube Racal RA117 or RA17 L with a LF adaptor and 100 hz of IF
selectivity plus a good audio filter. They are large but going cheap and
should do the trick.
73 de G3KEV