I took a look online and I think the Panasonic DP-UB450P-K (previously only available in Europe) and the optional disc drive on the Sony PS5 Pro (the same one they used for the PS5 Digital, about $80 USD) might be the last "new" 4K Blu-ray players selling.
Most of the other models (you may have heard LG just discontinued Blu-ray) are old and the newest 4K players were first released 5 or 6 years ago.