Finally looked into this (by downloading the database of "lies") and the 30,000 number is total crap. Most of them are just opinions or statements that require an extreme amount of nitpicking. For example
"We built the greatest economy in the world" (counted as a lie over 300 times)
"Lowest unemployment in 50 years" (ackshully it's 49, counted as a lie over 100 times)
"We need people at 3.7 percent unemployment, but they have to be brought in the legal way. And they have to be -- we talk merit. We want to bring them in through merit. We want people that can love our country and people that can help our
country." (Counted as a lie for no reason - he's just stating a policy preference - and the fact check doesn't explain why it's even misleading)
I have no doubt if you nitpicked every sentence Joe Biden said to the same degree you could find thousands and thousands of lies. But the Washington Post team that ran this database appears to have been disbanded in 2021.