As per the DMX standard, a maximum of 32 devices can be daisy-chained to any single DMX feed (i.e. 32 fixtures can be connected per DMX output).
To increase this quantity or simplify running cabling, you may wish to introduce more DMX Splitters to your system or use DMX notes or gateways.
More can be found about the DMX Standard (ANSI E1.11 – 2008 (R2018). Entertainment Technology—USITT DMX512-A) on the ANSI website https://tsp.esta.org/tsp/documents/docs/ANSI-ESTA_E1-11_2008R2018.pdf.