But won't this decision mean that there will be many more interventions by courts in things they have no expertise in? And those who don't like particular regulations will be tying agency managers up in court cases and preventing effective implementation of laws passed by Congress?

I don't think that's right. For starters, courts have enormous expertise in interpreting statutes - for federal appellate courts, it's a huge part of their job, and they do it all the time. And most rules of any consequence or that deal with contestable interpretations of statutory authority end up getting litigated anyway - and certainly of late, since Chevron has been whittled away at for the last several years.

That doesn't mean it won't have an effect. Agencies will lose some of those cases now, since they don't have the presumption. It's likely that some more cases will be brought, and agencies will likely be a little less aggressive in how far they push their interpretation of statutes. Whether that helps or hinders "effective implementation" of the statutes is something reasonable minds can disagree with.