oh man, I feel you on the wideshot panel woes. (I wish there was a site for horizontal strip comics...)
At 940px width any page comic (particularly one wider than tall like yours) is going to look blurry and undersized, but there's a couple little things you can do when you resize - under resize settings select "bilinear", which is meant for reducing resolution, instead of the default "bicubic" (I use Krita, but I'm pretty sure this is the standard options), and play with the image sharpening tools after resizing.
I also personally find jpegs sometimes end up blurrier than pngs, particularly if you reopen and edit them a couple times.
However, I would seriously consider chopping up your pages for a vertical scroll. I took a look at your comic on your site, and it looks like while your pages are overall wider, the majority of your panels are fairly square, and would be fairly easy to re-cut and convert to scrolling.
I'm not sure about the chapters you haven't posted yet, but so far in chapter 1 it looks like the only pages that will be hard to re-cut are page 4 and pages 21-23, mostly because of the background effects (nice work on those, btw).
Honestly as far the panels themselves go, I don't think I saw a single one that was too wide to work in a vertical format. (if there are some I missed, or some wide panels in pages you haven't posted yet, feel free to correct me either in DMs or here in the thread).
I also think some of your pages, like page 20, are already halfway to being a vertical layout - so re-cutting to vertical might even end up being a fun experiment for panel layouts in general.
I know reformatting pages for vertical is a huge pain to do, particularly if you've got a huge backlog to re-cut, but if you want to make it easier for Tapas and mobile readers to find and enjoy your comic, it's 100% worth the time and effort.