Your broker is not serving you properly.
A conversion of an RMD is a "failed conversion" that reverts to being a regular contribution. What became a regular contribution for 2022 is eligible to be returned before the due date of your 2022 tax return to avoid the 6% excess-contribution penalty for 2022 that would otherwise apply.
If you take a regular distribution instead of a return of contribution distribution, that will correct the excess for 2023 but you'll still have a 6% penalty on the excess for 2022.
