There's very little I can think of that seems to have changed about the site in the last 2 years for results from tripling their headcount.
Citation for the old headcount: https://www.theverge.com/2021/2/9/22274077/reddit-funding-ro...
Granted, I have no idea what scalability Reddit has done in 2 years. You can even argue it didn't need most of it (some, sure. Pandemic did surge traffic).
There's very little I can think of that seems to have changed about the site in the last 2 years for results from tripling their headcount.
Citation for the old headcount: https://www.theverge.com/2021/2/9/22274077/reddit-funding-ro...