Usually the last year of production of a model is the one in which sales are lowest (this is the case with the 3-series), many people preferred to wait for the LCI instead of buying an "older" car. I expect a strong increase in sales in 2023 for the 3-Series LCI.
In any case, in my opinion the pre-LCI G20 is much better looking than the LCI both in terms of aesthetics and interior, and since there are no significant mechanical improvements, the 'old' one is a better buy and I don't see a reason to get the new one, but that's just me
