so how do i know what rs im playing?

i see posts for like rs3 and osrs

i know what old school is but im playing the newer one on steam so is that rs3?

you are playing rs3

ok so what is rs2 then? is there even a thing?

i thought there was just rs (the new one) and osrs (old school obv)

Rs3 and osrs are the two variants. Rs2 is what preceded RS3. Essentially Rs2 became Rs3

OSRS is rs2, the 2007 version of it + added on updates in the recent years.

the old rs2 became the current rs3 aka Runescape pretty much, as xrmd said and that's the version that is available on steam right now.