Check with the sim centre and state of licence issue as they will be best informed, but…
I converted to EASA on a type I had <500 hrs on as part of the licence conversion skill test, and added that type to the EASA licence. Subsequently I can add additional ratings I do have more than 500 hrs on by renewing them with an EASA LPC and any additional training required by the ATO depending on the length of expiry. Initially I had understood I had to have 500 hours on type to convert the licence as this is what I was told, but clarified and it was a requirement for converting subsequent types via a simple LPC.
If the above isn’t applicable to your original licence, completing the skill test on E190 should grant you that type on your EASA and then have to figure out a way to get 500 hrs on the 73 as fast as possible.