I opened a thread some time ago for this as my 30k songs collection in my 1TB SSD is excruciatingly slow to search and navigate. Denon replied saying that, as long as we were using 1TB SSD drive, it should be good, and that they had tested with up to 70k songs and it was fine.
I am no experiencing the same and I have ended up splitting my collection in two different libraries, which I’,m not very happy about.
I don’t think the number of songs analysed matter a lot for searching and navigating the database. They do, as analysing the songs add the KEY and BPM fields to the database, but the important factor is number of songs.