No, the Insta360 Ace Pro 2 is not compatible with the Lexar Professional CFexpress Type A Gold 256GB.
Insta360 Ace Pro 2 has a microSD-only card slot (no CFexpress support of any type). Its own product page confirms only microSD card compatibility -- CFexpress Type A uses a physically different, much larger connector and cannot be inserted into a microSD slot.
What works instead
See all compatible camera for the Insta360 Ace Pro 2 →“Please use a Micro SD / TF card that meets the UHS-I, V30 or higher specifications and is formatted as exFAT.”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)