In my opinion yes I think it does
Soul Eater is an amazing anime with a questionable ending, I still love it to death even though its a terrible ending. Pluto which isn't an anime but a manga doesn't have a satisfying ending to me at all which made me give it a 9.5 instead of a 10 but is still one of the best manga I've ever read.
If an ending is bad but the anime is all around enjoyable then it won't take away from the experience I had while watching it, but i'll still be upset about the bad ending
I think it depends, I don’t know if you’ve watched it but for example “Durarara” was a REALLY good anime with a decent plot but the end of the anime wasn’t satisfying at all, yes it ended happily but it felt like there wasn’t enough. With that I don’t think the ending by itself ruined the anime or my perspective on it, but it DID ruin my satisfaction after i finished the anime.
If the ending is bad then it ruins the overall shows buildup. The show couldve been a solid 8/10 but then drop to a 7/10 because of a bad ending.
ANALOGY: Imagine if a waiter gives impeccable service, but then you find out that the waiter had stolen ur credit card info. Most people would try to reason with it in their head as to why the waiter had to ie; maybe they need to feed there family. But in the end, the customer will still have a lower view of the waiter than what he/she/they previously had.
A bad ending can definitely worsen any show significantly, but I believe on some occasions people tend to focus way too heavily on a bad ending and forget how much good there was before that. IMO people should still be able to appreciate all of the good things it had to offer during the course of its run, even if the ending did not live up to what came before, and not disregard the whole work in its entirety for missing the mark at the end.
@cosmonautic: refer to my previous comment about this issue
The best example of that
DARLING in the FRANXX
This discussion has been [Locked] due to @iDownward ending the discussion with straight facts.
I haven't seen Darling in the Franxx yet. But to me it seems like the ending brought the show to a higher tier. Other than that it would have been an anime with stupid things in it. The stupid thing here would be the way they pilot the robots, I guess. If it ended normally it would be an anime with a stupid thing in it. But it seemed like they brought the whole anime on a stupid-level so that everything can end in harmony. Which is far better than one more standard anime with a special something in it. That's what I think.
If the final episode alone was bad it would have been... actually no. Even in the case of only the last episode being bad, the show as a whole would have introduced far too many red herrings and plot holes for that to be even remotely successful. The only way a "bad" ending would have been OK is if they went Full Gainax and only Gainax can go Full Gainax.
DitF isn't a good series with a bad final episode. DitF is a potentially great series ruined by a trainwreck of a second cour.

I'd say some, but not all. If a show was mainly building up its story only to have a bad conclusion, it would leave a bad impression on me. But something like Samurai Champloo where it left me with a somewhat unsatisfying ending, it doesn't make me dislike the show as a whole since the show was more of the journey than the destination.
For anime? It largely depends for me.
But for manga, I don't think it matters as much. For example, I read and followed Domestic Girlfriend for a good couple years and it was an amazing manga but many think the ending was bad. I was meh on the ending, but I still think the overall manga was great.
When it comes to anime, it depends on the pacing of the anime for me. If the pacing and the content of the anime fits and is good, I think I'm more likely to let a 'bad' ending go if the anime was longer than a cour and I enjoyed the journey.
Someone mentioned Soul Eater. This is a good example of this for me.
It depends on the rough percentage of the anime I think it ruined. Nanbaka, which started as a comedy and was perfectly fine that way, eventually changed to become a battle shonen. The ending of the anime...
...it doesn't actually resolve anything. It just leaves everything hanging in the hopes it can get another season. Keep in mind season 1 was aired on TV, but season 2 was ONA. This is a case where I think the ending ruined the battle shonen part, but the comedy part was fine (as evidenced by the OVA which came out post-season 2 - that went back to being a comedy).
Similarly, Kado changed drastically after a certain point and I believe the original ending ruined everything from the turning point to the end. However, Kado had an alternate ending (Beyond Information) released, which is why I refer to an "original ending".
For an anime where the ending wasn't as sound as it could be but I think it was still consistent with the rest of the anime's logic when taken as a whole experience (e.g. ID: Invaded), I don't think it ruins the anime.