50mm at f/1.8 is radically different from 50-55mm at f/5.6, so the prime has a decided advantage here. However, 24mm at f/2.8 is not so radically different from 24mm at f/3.5. One option you may wish to consider is the 10-18 STM + 24 STM + 50 STM (would be nice if Canon made a 10 / 2.8 STM and 15 / 2.8 STM -- perhaps they will, in time).
EOS M6 + EF 24mm f/1.4 USM II (left) and the EOS M + EF 22mm f/2 STM lens (right) I removed the even larger Canon brand lens hood and replaced it with this one (left) to cut down on size. The EF-M lens doesn't require a lens hood although canon make a strange little tubular one that nobody else seems to buy.
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