Can the 2027 Cadillac LYRIQ make a U-turn?

Yes. Fits a 40 ft street.

39.6 ft turning circle

Turning circle of the Luxury RWD.

Street width, feet

Street 40 feet curb to curb.

2027 Cadillac LYRIQ Luxury RWD. Top view, to scale.

Source marks: one source

2027 Cadillac LYRIQ: turning circle by trim, 40 ft street
Trim	Circle, ft	Margin	U-turn without reversing
Luxury AWD	39.6	+0.4 ft	Yes
Luxury RWD	39.6	+0.4 ft	Yes
Sport AWD	39.6	+0.4 ft	Yes
Sport RWD	39.6	+0.4 ft	Yes
Premium Luxury AWD	39.6	+0.4 ft	Yes
Premium Luxury RWD	39.6	+0.4 ft	Yes
Premium Sport AWD	39.6	+0.4 ft	Yes
Premium Sport RWD	39.6	+0.4 ft	Yes
Signature Luxury RWD	39.6	+0.4 ft	Yes
Signature Sport RWD	39.6	+0.4 ft	Yes
4dr LYRIQ-V AWD	39.6	+0.4 ft	Yes
V Premium AWD	39.6	+0.4 ft	Yes
Signature Luxury AWD	39.6	+0.4 ft	Yes
Signature Sport AWD	39.6	+0.4 ft	Yes

What this cannot tell you

Curb-to-curb turning circle as listed.

Mirrors and overhang need more room.