I'm afraid that's a "how long is a piece of string?" type question. Putting a mast up is the very visual bit, but there is then a lot of connections and network configuration to go through, and then probably a couple of months testing phase when signal can come and go.
The mast in your picture is 5G and as all 5G at the moment is None Stand Alone it has to work in tandem with a 4G mast. That may want strengthening.
This is not O2 and we are all customers here similar to yourself and cannot answer account type queries.
