Here are bookmaker limits. Notice the Football and Baseball limits.
https://www.bookmaker.eu/wager-limits
For the NFL, there's $10,000 limit on the opening sides, but it's $3,000 for opening Totals.
On game day, there's a $50,000 limit on sides but it's $20,000 on Totals.
For overnight NCAAB lines, big bad Bookmaker will only take $500 bets.
There's a reason Totals are so much less.
If you scroll down the link, you'll find that only the NHL has the same limits for sides, totals, and moneylines. They probably thirst for action.
The bottom line is, and has been since before there was an internet, that the books are a bit more scared of sharp Total bettors than anyone else in the book.