Are The Simpsons still good?

No.  It's widely agreed that the Simpsons was one of the best sitcoms of all time for it's first 8-10 seasons.  Where EXACTLY you draw the line is subjective.  But by season 11, pretty much everyone agrees that Simpsons was garbage.  It was just catch phrases and over the top exaggerations of the characters that had come before.  It was pointless celebrity cameos for no reason.  It had become the worst version of everything it used to satirize.

The Simpsons still have some good episodes, some are not so good.

No, Simpson were better before, family guy is better now

I recently watched the entire series (up to season 31) on Disney+.  The first 6 seasons or so were good.  Around season 7-8 it really took a nosedive.  However, it mostly recovered by season 11 or so.  Since then the show has been like any other TV series - some episodes are good, others are bad.  I'd say the last few seasons have actually perked up a bit.

Not without Apu Nahasapeemapetilon

At this point. With me, it's a matter of pride. I've watched it from the very first short to this day. 31 YEARS!