Security takes a little longer per request because of the encryption/decryption that has to take place.
If you are in a situation of using your own network, then things will be faster without it.
Thanks for getting back to us with the error number(s). I have also seen the -5 error when doing a lot of requests.
Make a dummy table 80 to 100 elements long in the control strategy. Do a test read on that table.
In other words, it should be a lot faster and more efficient to do a single table read than to read 26 analog inputs and 19 digital inputs.
If this is the case, then you just need to tweak the strategy to build that table and then have Node-RED read it.
You are on the right track, it could be a load issue. groov also is using the REST interface, so if it is reading a lot of tags and Node-RED is also reading a lot of tags, then things get loaded for the controller.
We are working on the issue here with the software team and hope to get to the bottom of it, but we have nothing to share other than the tip that reading a block via a table is more efficient.