Correct. If you want the $50k Roth conversion to be 2023 income, the distribution from the traditional IRA must be made no later than December 31, 2023 and will be reportable on your 2023 Form 8606 Part II (along with Form 1040 line 4).
If you want to do a Roth conversion in 2024, you'll similarly have to complete your 2024 IRA RMD first before converting any other traditional IRA amounts to Roth.
