"Starting again is a much safer option"
Nope Nope Nope Nope Nope Nope Nope and once again nope. If that was an option this post wouldn't exist so please stop, I'm tired from all this "advice" that is anything but helpful, why every internet forum has to be like this?. . .
Back to the topic, well, I flipped the flag for Nprs and then used delete race button in game. Performance boost was huge, sure, I got a few db errors next time I opened the game, but to be fair I had some errors popping up at random points long before this for apparently no reason at all, I got used to it, nothing seems to be affected by this change so far except my performance skyrocketed.
What could happen in the worst case? My save will blow up at some point, but that's it, so after investing a few dozen hours into it I feel like continuing and starting over only if save-corrupting bug will destroy my current game rather than just giving up and going through all of this once again.