The number of baptisms has declined significantly as a percentage of members since the mid 1990s. The growth rate has declined significantly during this period as well. This is different than a decline in membership.
You can easily tell when JWs begin declining overall because the it’s when the number of members gets smaller year on year. So far this hasn’t happened apart from one year following 1975 and one year during the pandemic.
I very much agree that the number of congregations is a crucial statistic and there has indeed been a small decline in the number of congregations in recent years. It will be interesting to see if that continues. The number of publishers has also shown a decrease in Latin America in the past few years. JWs didn’t seem to bounce back in Latin America after the pandemic as they did elsewhere. It will be interesting to see what happens here too.
In contrast with JWs, most Protestant denominations are in steep decline in most western countries: not simply slow growth or few baptisms/converts, but actual, rapid decline in membership.