ORM

For a new big and convoluted project I (am/was) using Devart´s 
LinqConnect as ORM.
But today I experienced some inexplicable "object reference not set to 
an instance of an object" exceptions or other more specific to this 
libraries.
I would wish to change the ORM.
Some experiences would be appreciated. Of course, I prefer open source 
software, at least to chase errors thru debugging.
TIA

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