With a 16GiB on your computer, you should not see any hesitations for a doc of only 200 pages…
Maybe it is the way you wrote your document… or your operating system…
As a test I downloaded the .odt here => Writer Guides | LibreOffice Documentation - Your documentation for LibreOffice which is a 448 pages doc with a quite complex formatting (100s of tables, images, and so on…) it is as smooth as a breeze, no hangs or what so ever, all test’s edits AND scrolling down to the end are instantaneous at any pages number 100+, as well as 200+, 300+, 400+…
Tests made on my 4 years old computer with only 8Gb of RAM (Ubuntu-MATE 19.10 / LO 6.4.2) as well as on my laptop (4GB ram / Ubuntu-MATE 18.04 / LO 6.0.7.3) everything is very smooth as expected, I even tried some clicks on the TOC and they all bring me instantaneously to the desired page at whatever triple digit is the page number