Star Trek: 10 Secrets About The USS Enterprise-G You Need To Know
6. Shangri-La La La Laaa
The Enterprise-G can trace its design history back to the 23rd Century as part of (conjectural) Star Trek canon.
In the observation lounge during season three of Picard there are three distinct models on show echoing the Enterprise-D lounge, the E's glass cabinet and little ships (very fragile apparently) as well as the pieces on display aboard the Stargazer.
The Shangri-La Class was in use during the 2370s with the original USS Titan, commanded by one Captain Saavik.
The Constitution III class was effectively a 25th Century update for the Shangri-La class with the Titan providing some form of design and name lineage. As the designer of that class, Bill Krause explained, the Titan-A included upgraded engines to differentiate it from the original. This also added that 2401 touch to the ship but even then they're actually inherited from another starship.
Those engines were in fact taken from the season two hero ship, the USS Stargazer - with modifications so that they could be opened and tinkered with by the grease monkey in charge.