Was I supposed to get a W2 if I'm retired from the federal government and only got a 1099R from OPM?

Well...in the year you actually retire, you'd get both.

1)  A W-2 for the time you worked in 2022

2)...then a 1099-R form for all the retirement $$ you receive after retiring.

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IF you were retired all of 2022, then it's rare, but possible to get a W-2 for some smaller amount if you retired right at the end of 2021...if the last pay period happened to slop into 2022.

It depends.  Did you actually work for the employer for any part of 2022? If yes, you should get a form W2 showing your pay for that period.  The form 1099R would only be for distributions from your retirement account.   

If no, meaning you were retired for all of 2022 then you would only get a form 1099R showing distributions from your retirement account.  No form W2 would be issued.