So it is a new game but not a new game.
Consider this.
The Street Fighter franchise has six mainline "editions" to it. However, each mainline edition has had several iterations (for example: Street Fighter 2 has Champion Edition, Turbo, Super, Super Turbo, and Ultimate just to name a few). Each version brings balance changes, new moves, bugfixes and new characters. If you are a serious player, you know Ryu doesn't play the same in Vanilla SF2 as he does in Super Turbo, despite both being iterations of the same game (SF 2). It gets even wilder when you consider all the spinoff games (the Alpha Series, the Marvel crossovers or the SNK crossovers) that further play differently and have unique mechanics and spritework. Yet in every one of them, Ryu is a shoto, his core moves (fireball, dragon punch, hurricane kick) are there and done using the same joystick/button movements. You can talk about Ryu in a broad sense and players will know what you are saying, even if they play SF3 Third Strike, SF5 Arcade Edition, or Marvel vs. Capcom Infinite. Lingua Franca.
D&D is a lot like that. Five major editions, several spinoff editions, and plenty of games that play suspiciously similar to it or take inspiration from it. I've electing to view the 24 rules as being akin to moving from SF2 to Super SF2; new art, new moves, more characters, fundamentally the same baseline. The finer details will have changed, but the core gameplay is the same. It's a far smaller jump than between SF2 and SF3 or SF4 which bring in all new mechanics and very different rosters. The truly dedicated see the difference (there is a reason in SF2 Anniversary collection you can select the previous versions of any SF 2 fighter; each one has minute differences that might be lost on all but the most hardcore player) but for most casuals, Ryu is still Ryu and fireball is still down/down-forward/forward + punch. For most, One D&D/2024 will be that kind of evolution. They will see the shiny new graphics, the updated movelists, the new characters, and character rebalancing and think "oh, cool, SF2 got an upgrade" not "WTF, Sagat's heavy tiger knee no longer crosses up an opponent allowing for a free mixup combo!"
Hmmm... Maybe we should start calling the new Rules "Champion Edition"?