Is it ok to connect batteries in parallel?
Making the assumption we are talking about non-rechargeable batteries here, then I would say No, don't do it.
However, if you are building a bank of batteries that will be recharged (as in a UPS, or a Solar backup), then you can, and may often do, add batteries in such an array.
Here is a link that may explain more and give some examples of good ways and bad ways to put a battery (which is, after all, a collection of cells) together.
https://batteryguy.com/kb/knowledge-base/connecting-batteries-in-parallel/