You can’t sadly. The only possible transfer of progress can happen from H2 to H3. within the same platform roughly.
You can’t for free in this case. It would be possible if you owned H2016 on Steam, but EGS → Steam is not a thing. You would have to buy the Legacy Pack for H2.
What you could do is to use the same IO Account to log into both H2016 and H2, buy Hitman 3 on EGS, and again use the same IO account here as well. If you follow the transfer progress, you will move your (nonexistent) H2 progress. But on the plus side, it should unlock both the H2016 and H2* levels in H3. That still is no free solution but at least comes with more content than you have with both first games.
* Note that due an ongoing issue redeeming H2 from Steam in H3 on Epic is not fully working until later this month.