Hi @tuanphan! Thank you for following up. Unfortunately I have not yet solved this, as every fix seems to cause a new error. When I added the code above I was able to fix the column and footer issues, but still experienced the choppy/lag loading on mobile and then noticed this code update also displaced the footer navigations in the desktop version of my site, placing them higher and overlaid on top of the gallery images. Since it seemed to be doing more harm than good, I deleted the code and have left it alone for now.
It appears from viewing @Frames_by_Saurabh's site on mobile and desktop that they were able to fix the issues I'm having without any major visible glitches on desktop or mobile, but I haven't figured it out yet.