The Dreamcast possibly just needs the laser tuned a little
Can't say I have had an issue playing burned media on my Dreamcast though, but have tuned the laser a couple of times to read CD-R's better
As for PCECD I can't say as I never had one or a Sega CD for that matter
my PSone still runs just fine as does my Saturn and both play CD-R's
PSX's (including the PSone) are more prone to the silly little CD clip things to drop apart and that makes reading CD-R's almost impossible and originals may start to struggle also
The laser in the PSX is especially bad though