Unless you are flying from a location where Virgin have a Clubhouse (that is open too), then the lounge offering for UC passengers is not great.
The lounge they used to use in Manchester (Escape Plus) was halfway OK - you could always get a seat. That is in old T2 now, so closed, they now use the 1903 lounge in new T2, I will reserve judgement on that until mid-June when I'll pass through it.
As to Orlando, the Delta Sky Club is like entering a 1980's time-warp in terms of decor. It can get very busy and it can be difficult to find a seat - let alone two or 3 seats together at busy times. This lounge used to be much larger too - they cut it's size by a lot some years ago (long before the pandemic).
Asa rule of thumb, no US airport lounge is anything special - unless it is restricted to International First / Business Class passengers only. Lounges like the Delta Sky Clubs can allow paid access is capacity exists & the US airlines have way too many frequent flyers with status to fill their lounges, or flyers who hold the right credit card to permit them access.