Unfortunately we’ve exercised previous efforts in getting API Explorer to work with large APIs where it no longer uses JSONP to workaround the exceeded JS method callstack errors, so now you’re just hitting the resource limits of your browser & pc for handling the App metadata & render its UI.
Only real solution I can recommend is splitting your App into smaller microservices to reduce the App size & resources burden.
There’s also a potential for reducing the APIs you want to show up in API Explorer by modifying the metadata returned to reduce the APIs included in API Explorer, e.g. by not including APIs grouped within a tag:
this.AddToAppMetadata(meta => {
meta.Api.Operations.RemoveAll(x => x.Tags?.Contains(tagName) != true);
});
Out of curiosity how large is your /metadata/app.json
?