Great request! Also Helvetica should not be the default. It’s no scientific news that it is not a good font for long reads. Neo-grotesques like Helvetica with closed apertures have have a poor legibility. Also this distinct font looks too heavy and too tightly spaced in dark mode.
Yes please, being able to change the reader view font easily would be very welcome.
On Windows, the Arial font renders poorly for me with letters running into each other probably in part due to the letter spacing being reduced: --letter-spacing: -0.03em; --word-spacing: -0.05em;
This actually makes readability worse, somewhat defeating the purpose of the reader view. Giving control of appearance would help.