CD Player: Vintage or modern ones?

The only old CDP's worth considering AS TRANSPORTS are the TEACs, as in the VRDS mentioned above. TEAC had excellent transport mechanisms, even in their less fancy models (they still do, but it's now called "esoteric" and costs a fortune).

Digital to analogue conversion has generally improved in the past 20 years...

Keep in mind however that lasers have a finite life expectancy, so you might be better off purchasing something new

You’re possibly be right both of You, the other options is a Lascala MKII DAC and enjoy streaming.

Budget?

DACs have improved quite a bit since the dawn of the CD era.  This would include the the DACs contained in CDPs.

it’s unclear to me if the OP streams currently.  If he does not and is interested in doing so then a streaming DAC with a CD transport combination makes a lot of sense.

Transports and DACs have improved a lot over the last couple decades. So, newer much better. But the technology has also advanced. Streaming will offer the same sound quality (carefully chosen, compatible like everything else in high end audio), but you get access to over 10 million albums and over half a million of high resolution (higher than CD quality) with a service like Qobuz… $14.99 / month… the price of a single CD. I have 4,000 albums and have not listened to them in years. To do this you need a DAC and streamer… separated are best.

How do older cd players age, even when they are not put in use, for long periods of time?  I asked ChatGPT and got some surprising answers.