As of today, unity is worth 10-12bi, Ironsrc intended to go public at around 11bi last year, now they are being acquired at 4.4bi. Ironsrc main competitor, AppLovin is worth 12bi.
Ironsrc 2021 revenue was 553m, Unity revenue was 1.1bi. However, Ironsrc had a net income of 21m and Unity had a net loss of 531m. Both hold around 0.7bi and 1bi in cash respectively.
So is Ironsrc much smaller? I do not think so.