I went from Foxit to the XChange Viewer for some reason I can't remember. Then the XChange Viewer really screwed up the installation two years ago (a deinstall helped) and I switched to the Nitro PDF Reader:
https://www.gonitro.com/pdf-reader
They even have a 64bit version. The Nitro Reader also has a whole bunch of editing options. I really like it.
Have you tried using the Books app included in macOS? It also handles PDFs, and off course .epub.
If you want a separate application that's Non-Apple and Non-Adobe there are many alternatives both free and paid. PDF Expert is probably the best if you want advanced PDF capabilities, but it is rather pricey (€79.99).
There is also PDF Elements from Wondershare, but it is not free either ($69 / yearly).
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Good free alternatives include:
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Try them out, I'm sure you'll like one of them.
I just posted this above, but my choice is Nitro. It's been a while since I used Sumatra, but while Nitro is not as lightweight it does have a good amount of features.
I prefer Nitro PDF over Sumatra and Foxit. I don't remember the specifics, but I felt like those two were either lacking in features or asking me to upgrade. The downside of Nitro would be that it uses a bit more memory, though my relatively low-end PC handles it just fine.