As illustrated in Simulate API rate limit exceeded on Exact Online sync APIs, the restart capabilities have improved enabling cross-day initial downloads. The theoretical maximum volume is now tables with 50 * 5000 * 1000 = 250 million rows per Exact Online incremental table, given sufficient time. Companies with over 10 million rows in a transaction table are hard to find on Exact Online.
The improved restart capabilities are available in all version 22.0.92 and up.