In reference to the subject question, I note that there have been several recent publications on the Classical Sicilian. That suggests that the Classical Sicilian is not "that bad." I suppose one could see it differently, as the last gasp of a bad line. Why not share analysis in a line that you do not intend to play? I'm inclined towards the more optimistic interpretation.
Recent publications on the Classical Sicilian:
Classical Sicilian - Expert Repertoire for Black by GM Ivan Cheparinov , June 19, 2022
https://www.modern-chess.com/classical-sicilian-expert-repertoire-for-black-appr...Understand the Classical Sicilian by Modern Chess Team, October 13, 2021
https://www.modern-chess.com/understand-the-classical-sicilian-7-5-hours-running...Lifetime Repertoires: Classical Sicilian by GM Sam Shankland
https://www.chessable.com/lifetime-repertoires-classical-sicilian/course/68589/The Richter-Rauzer Reborn, The Kozul Variation by Zdenko Kozul and Alojzije Jankovic, Jan 21, 2020
https://forwardchess.com/product/the-richter--rauzer-reborn,-the-kozul-variation...Play the Classical Sicilian - Complete Repertoire by IM Ogulcan Kanmazalp, February 22, 2019
https://www.modern-chess.com/play-the-classical-sicilian-complete-repertoireComplete Rauzer Repertoire for Black by IM Ogulcan Kanmazalp, February 1, 2019
https://www.modern-chess.com/complete-rauzer-repertoire-for-blackI enjoy playing the Classical Sicilian because the players often find themselves on their own, just playing chess, in sharp lines where Black has chances. In my opinion, the only existential threat to the Classical Sicilian comes from the Rauzer variation. I have the books by Kozul and Kanmazalp. They both feature 9...b5. Titles by Shankland and Cheparinov feature 9...Be7.
The 9...b5 line seems very linear. Black proceeds with an almost single-minded focus on attacking the white king. Some of the lines run deep. As far as I can tell, Black is hanging in there.
The 9...Be7 lines seems less committal. I have not bought either Shankland's or Cheparinov's book. I don't know how the Modern Chess Team addresses 6Bg5. As the team is composed of several authors, I suspect that multiple answers are provided.
Shankland also covers anti-Sicilian lines.
The two most recent titles from Modern-Chess contain video and are expensive. However Modern-Chess is running a 45% off sale on all their products at the present time.