I was made aware that such suffix is used to provide information on the radio model and that an entry needs to be added to https://github.com/aprsorg/aprs-deviceid/blob/main/tocalls.yaml in order to hide such suffix on
aprs.fi. Another radio that I use,
FT-5DE, is suffixed by _3, but on this model such suffix is properly hidden when browsing on
aprs.fi. This models seems to have an entry on the YAML file above.