Acrobat Reader DC 2021.007.20099 "Out of memory" all the time with 2+ files open

I am using Acrobat Reader DC 2021.007.20099 (i.e. the latest build) to view PDF files that are scanned books, where pages are images with text overlays.

It works fine with a single book, but if I open 2 or more books, in short order after paging down just a few pages I get "Out of memory error". This happens consistently, all the time, does not depend on any particular file, happens with all/any of them.

SysInternals Process Explorer shows that private virtual memory use (private working set) in process ArcoRd32.exe at that point is 3.7 GB.

Windows 7 x64.

Something is obviously very wrong with how Acrobat manages memory. The whole size of on-disk PDF files is much smaller than that, let alone what conceivably might be needed to keep in memory data for just several pages around the displayed one.