Most WD reds are CMR are perfectly fine. Look op the individual partnumber to be absolutely sure, as there are some that are indeed SMR.
I used a shitload of WD 4TBs. The WD40EFRX since 2016 in 24/7 usage. They were my go to’s before the 12TB (WD120EFBX) and 14TB (WD140EFGX)
@4.5W, 28dB and CMR, they are cool, quite, fast and durable little disks. They run what seem to be forever.
But do your due diligence beforehand as there is a wide spread in specs even within the same series within WD.
Do a full writing check from beginning to end beforehand.
But I don’t like my 8TB WD80EFAX ones. They run quite hot @8.8W. and IMO way more noisy than the other models I have of WD Red plus drives.
If the full check comes back clean, I would only use them for offline and external copies of data as they probably have a lot of running hours in real life. I hope you didn’t pay too much.