Thank you for bringing out the receipts. I saw that post and was like "Umm...nope".More nonsense from you. I can't really tell whether you're trolling or you're actually deluded, so kudos to you I guess.
As for Serena, she is the only player in history to win 3 Slams after saving match points (Australian Open 2003 and 2005 and Wimbledon 2009).
Apart from that, she also came back from 6-1 5-2 against Petrova in the 2007 AO and was 2 points away from losing to Peer in the QF. She was also 2 points away from losing to Kuznetsova in 2009 (was trailing 7-5 5-3), Azarenka in the 2012 US Open final (trailing 2-6 6-2 5-3) and Watson in 2015 Wimbledon. She also had ana epic comeback against Azarenka at the 2010 Australian Open, coming back from 6-4 4-0. Moreover, Serena has won more matches after saving match points than any woman in history.
Match points aside, Serena had so many successful returns after falling out of the top 100 (2007, 2011, 2018). Serena was also a mental giant in finals during her prime going 34-3 in finals between 2010 and 2015. Maria on the other hand had a 13-15 record in finals during that same time which was also her prime, including going 3-6 in finals in 2012, her arguably best season on tour (or at least on par with 2006).
Maria wad a great competitior and she was mentally tough, but she isn't in the same league as Serena, much less the "mentally toughest player in history" lol.