Nicholson's have a lot of pubs in and around London,and I would say that the dumbing down of the ale selection has been company policy since well before Covid.Once they got St Austell to brew their Nicholson's Pale,the offering often seems to be another St Austell ale,Tribute along with Sharp's Doom Bar and Fuller's London Pride.In London you may find a guest besides these regulars ,or you may not.
My last visit to the Philharmonic was in 2019 and the ale selection and conditioning was dire.I didn't update my review ,assuming that being an occasional visitor I just got unlucky on the night.Maybe not from what you have said.