Writer lags considerably in paragraphs with non-Western fonts

In my dissertation I need to switch between English and Hebrew (which write left-to-right and right-to-left, respectively). In paragraphs with only English, LO works just fine but in paragraphs with both languages, there is significant input latency. This problem only affects my desktop computer and not my laptop. Both systems are running Ubuntu Budgie 20.04 but the problem was present on my desktop PC before I did a fresh install up from 19.10. I’ve tried using the 7.0 beta and a wired keyboard but to no avail. Below is a screenshot of my system monitor readout. The flatter bits at either end are me rapidly typing gibberish in an all-English paragraph and the two peaky spots are me typing in English in a mixed Hebrew-English paragraph. I don’t get anything similar on either of my much less powerful laptops.