Team 19 is coming in 2028An uneven number of teams never lasts long.
NSWRL - 13 teams from 1984 to 1987 inclusive (4 seasons)
3 teams added in 1988
NRL - 17 teams in 1999 (1 season)
Competition downsized to 14 teams in 2000 as per peace settlement
NRL - 15 teams from 2002 to 2006 inclusive (5 seasons)
Gold Coast Titans added in 2007
NRL - 17 teams since 2023 (2 seasons & counting)
If this lasts for 5 seasons like before the Titans were added,
it'd be 2023-2027 inclusive & team 18 would debut 2028
Now, if you're thinking team 20 won't be until the late 2030s, that might mean team 19 doesnt happen until (say) 2032-ish, because if it's any earlier that's an unprecedented LONG time with an uneven competition size & weekly byes.
team 20 might be 2030