It certainly is NOT the latest, but I always found that the original Operations Flashpoint (Game of the Year edition) to be very well executed, and well worth a look. The audio quality and level to detail is very good (for example, when you fire a gun you can tell what it is by the difference in the sounds), while the AI is also very good for the era. It can be played multi-player, but the main storylines are very engaging (you can play either from the USA perspective, the Russian side, or the Resistance). The last (Resistance) also has the ability to link between missions; equipment gained in a previous mission should be available in following missions, while any equipment/personnel lost are unavailable in subsequent mission.
https://www.amazon.co.uk/Operation-Flashpoint-Game-Year-PC/dp/B0007VHHBW
While it may well be over 15 years old Codemasters got it very right. The sequel (Dragon Rising) has better graphics, but was not, in my opinion, as good as the original.
For a silly FPS "Armed and Dangerous" is quite a hoot. Weaponry such as The Landshark Gun or The Worlds' Smallest Black Hole in a Box add to the laughs. Produced by Lucas Arts it does, to a fair degree, point a finger of fun at some of the other Lucas products.
https://en.wikipedia.org/wiki/Armed_and_Dangerous_(video_game)