Thank you @BLUEFROG and @grosson for your help with this inquiry. I have played around with these suggestions and just wanted to summarize (perhaps for the help of future users) what I found:
- The problem with the increase in PDF size and inability to edit annotated versions has to do with macOS and not DT. This was tricky to discover at first from my end, as others explained in the thread, this is the case. Even if I make some annotations with other PDF programs outside of DT this phenomenon occurs. I would hope that this problem could get resolved, but I understand it is on the mac side of things.
- As @grosson explained, his workaround is helpful for the time being. I have worked through a large PDF around 450+ pages. I would ONLY annotate/highlight externally. That is I set my Preferences to “Double-Click Opens Documents Externally.” I chose to use Preview for this and made highlights. When I saved and closed the program, the file size stayed the same, the annotations were readable, and the document was searchable. However, anytime I would make an edit/annotation in DT it would make the PDF act the same way as described earlier in this post (i.e., increase in size, lose editable text, etc.)
- It seems (although I have not messed this as much), that when I edit/annotate the same PDF from DTTG on my iPad or iPhone that the edits stay are made on the desktop version when they sync, and the same problem does NOT occur. That is, for some reason I can edit a PDF using DTTG without a huge problem but when I use DT to highlight/annotate the problem occurs.
Anyway, it would be nice for the systemic problem to be resolved. However, for the moment, this at least brings me clarity to the issue at hand. I thank you all for your help in troubleshooting this!